Fuse questions, answered
306 questions about medium and high voltage fuses — what the ratings mean, which fuse suits which job, what replaces another manufacturer’s part, and what DENCO needs from you to confirm it. Every answer links through to the page that carries the detail.
Where an answer states a rating or a range, it is read from DENCO’s own January 2025 catalog. Where it defines an industry term, it cites the ANSI or IEEE standard that defines it. Nothing here is inferred by comparing one manufacturer’s specifications with another’s — on a fault-interrupting device, that is not a safe thing to do.
Fuse fundamentals
What the industry terms mean. These are definitions published in ANSI and IEEE standards, so they read the same whoever made the fuse.
What is a current-limiting fuse?
A current-limiting fuse melts and then introduces a high resistance so abruptly that it cuts the fault current off before it can reach its full prospective peak. It reduces both the magnitude and the duration of the current, and it does so only while the current is inside the fuse's specified current-limiting range. ANSI C37.40 is the standard that defines the term.
What is an expulsion fuse?
An expulsion fuse interrupts the circuit using the gases that its own arc generates. It limits how long the overcurrent lasts, but it does not limit how large the fault current becomes — the current runs to its full prospective value before the fuse clears it. That is the essential difference from a current-limiting fuse.
What is the difference between a current-limiting fuse and an expulsion fuse?
An expulsion fuse limits the duration of a fault; a current-limiting fuse limits its magnitude as well, clearing before the current reaches its prospective peak. The practical consequence is let-through energy: swapping an expulsion cutout link for a current-limiting design changes the energy the rest of the installation sees, so it is something to assess rather than assume.
What does full range mean on a current-limiting fuse?
A full-range fuse will interrupt any current large enough to melt its element, from the smallest melting current up to its maximum interrupting rating. It needs no other device in series with it to cover the low end. ANSI C37.40 defines the three current-limiting classes; which one applies to a particular DENCO part is confirmed by DENCO against that part.
What is a general-purpose current-limiting fuse?
A general-purpose fuse will interrupt any current down to the one that melts its element in one hour. Below that, an overcurrent can melt the element without the fuse being able to clear it, so a lower-current condition needs another protective device. It sits between full-range and back-up in the three classes ANSI C37.40 defines.
What is a back-up current-limiting fuse?
A back-up fuse interrupts only down to a stated minimum interrupting current. Below that current it must not be relied on, so ANSI C37.40 requires a low-current interrupting device in series with it. Back-up fuses are common in oil-filled transformer applications, where a bay-o-net expulsion link handles the low-current end and the back-up fuse handles the high.
What does the E in an E-rated fuse mean?
It is a melting characteristic defined by standard, not a manufacturer's designation. Under ANSI/IEEE C37.46 an E-rated fuse of 100 A or below must melt within 300 seconds at a current between 200% and 240% of its continuous rating; above 100 A it must melt within 600 seconds at between 240% and 264%. Because the criterion is defined rather than proprietary, an E rating means the same thing whoever made the fuse.
What does the R in an R-rated fuse mean?
An R-rated fuse must melt in 15 to 35 seconds at a current 100 times its R number, under ANSI/IEEE C37.46. So a 6R fuse melts in that window at 600 A. The R number is a melting characteristic for motor-circuit duty, not a continuous current rating, which is why R-rated fuses are selected against the motor's starting profile rather than its full-load amps alone.
Is an E rating the same as an ampere rating?
No. The number is the continuous current rating in amperes, and the E says that the fuse's melting behaviour meets the ANSI/IEEE C37.46 criterion for that rating. Two fuses of the same ampere rating, one E-rated and one not, will not necessarily melt at the same point on the curve.
What is an interrupting rating?
It is the largest fault current a fuse is rated to interrupt safely at its rated voltage. It is usually quoted RMS symmetrical, and for some products also RMS asymmetrical — the two figures are not interchangeable, and a fuse must be selected against whichever your available fault current is expressed in.
What is the difference between RMS symmetrical and RMS asymmetrical interrupting rating?
They describe the same fault current measured two ways. The asymmetrical figure includes the DC offset present in the first cycles of a fault and is therefore the larger number. A fuse quoted at 63kA symmetrical and 100kA asymmetrical has one capability stated twice, not two capabilities — compare like with like against your system study.
What is I²t let-through?
I²t is the energy a fuse allows to pass while it is clearing a fault, and it is the number that decides whether the device downstream survives. Semiconductors are the clearest case: a thyristor has its own I²t withstand, and the protecting fuse has to let through less than that. It is the reason ultra-rapid fuses exist as a separate product class.
What is a time-current curve?
A time-current curve plots how long a fuse takes to melt against the current flowing through it. It is what coordination is done on: the curves of the devices in series have to be arranged so the one nearest the fault opens first. Both a minimum-melt and a total-clearing curve matter, and they are not the same line.
What is fuse coordination?
Coordination means arranging the protective devices in a system so that a fault is cleared by the device closest to it, leaving everything upstream in service. For fuses it is done by comparing time-current curves. It is a study carried out against your actual system data, not a property you can read off a single part number.
What is the difference between a fuse's melting time and its clearing time?
Melting time is how long the element takes to melt. Clearing time is melting time plus the arcing time needed to extinguish the arc and actually interrupt the circuit. Standards criteria such as the E rating's 300-second and 600-second limits are stated as melting times, so a total-clearing figure will always be the longer of the two.
Do medium-voltage fuses provide overload protection?
Generally not, and it is the most common misunderstanding in specifying them. Most medium-voltage current-limiting fuses — R-rated motor fuses especially — are short-circuit protection devices. Overload protection is the job of a relay or an overload device, and the two are selected together rather than one substituting for the other.
What voltage is considered medium voltage?
In North American distribution practice medium voltage generally covers roughly 1kV up to 38kV, which is the band DENCO's transformer, motor, capacitor and PT fuse ranges are built for. Above that the terminology shifts to high voltage. The important number is never the label but the maximum design voltage printed on the fuse, which must be at least the system's.
Can a fuse be used at a voltage lower than its rating?
Applying a current-limiting fuse well below its rated voltage is not automatically safe, and it is not the same question as with a simple overcurrent device. The arc voltage the fuse generates while clearing is a function of its design, and its current-limiting performance is characterised at its rating. Send the system voltage with your enquiry and DENCO will confirm against the part rather than leave it to be inferred.
What does HRC mean on a fuse?
HRC stands for high rupturing capacity — a fuse able to interrupt a large prospective fault current without rupturing its body. It is the British and IEC term for what North American practice more often describes through the interrupting rating. DENCO's Type HH fuse-links are HRC current-limiting designs.
What is an ultra-rapid fuse?
An ultra-rapid or semiconductor fuse is designed for very low I²t let-through so that it clears faster than the solid-state device it protects can fail. That speed is its whole purpose, and it is also its limitation: it is not a substitute for general-purpose overload protection.
What is a fuse barrel, and why do some fuses have more than one?
The barrel is the tube that houses the fuse element. Higher-current ratings need more element in parallel than one barrel can hold, so the fuse is built as a double or triple barrel assembly. It matters when replacing a fuse: the barrel count changes the physical envelope and the mounting, so a single-barrel part is not a drop-in for a double.
What is a clip-mounted fuse?
A clip-mounted fuse is held by spring clips that grip its end ferrules, so the dimension that matters when replacing one is the clip centre distance — the spacing between the clips — as well as the overall length and diameter. DENCO's catalog publishes clip centre as a dimension column for exactly that reason.
What is a bolt-in fuse?
A bolt-in fuse is fastened by bolted terminations rather than gripped in clips, and the dimension to match is the bolt centre distance. Clip and bolt mounting are not interchangeable even where the electrical ratings are identical, so the mounting style has to be part of any replacement enquiry.
What is a striker or indicator pin on a fuse?
A striker is a spring-loaded pin that pops out when the fuse operates, giving a visible indication and, in many designs, mechanically tripping a switch or contactor so all three phases open together. Where a striker or microswitch is fitted, a replacement fuse must carry the same provision — a fuse that fits electrically but lacks the striker will leave the trip function missing.
What does gPV mean on a solar fuse?
gPV is the IEC utilisation category for a photovoltaic fuse — a full-range fuse characterised for the DC conditions in a solar string, where the current is limited and the voltage sustained. It is not the same duty as an AC fuse of the same ampere rating, and an AC fuse should not be substituted into a PV string.
Why can't I use an AC fuse on a DC circuit?
An AC current passes through zero twice a cycle, and fuses rely on that to extinguish the arc. DC has no zero crossing, so the fuse has to force the arc out unaided — which is a different design problem and a different voltage rating. A fuse rated 1000VAC is not therefore rated 1000VDC, and DC ratings are stated separately.
What is a fuse's minimum interrupting rating?
For a back-up fuse, it is the lowest current the fuse is rated to interrupt. Below it the element may melt without the fuse clearing the circuit, which is why ANSI C37.40 requires a series device to cover the low-current range. It is quoted alongside the maximum interrupting rating, and both have to be satisfied.
Does a fuse need to be derated for ambient temperature or enclosure?
Continuous current ratings are established under defined test conditions, and a fuse in a sealed enclosure, at altitude, or in a high ambient will not behave as the published rating implies. Derating is application-specific rather than a single factor, so send the installation conditions with your enquiry and DENCO will advise against the part.
What is prospective fault current?
Prospective fault current is the current that would flow at a point in the system if a fault there were not interrupted — the figure your fault study produces. It is what a fuse's interrupting rating must be compared against, and what a current-limiting fuse prevents the actual current from ever reaching.
What is peak let-through current?
Peak let-through is the highest instantaneous current a current-limiting fuse actually allows through while clearing, as against the peak the fault would otherwise have reached. It is the measure of how much a fuse limits, and it is what the downstream equipment has to withstand. Comparison charts of peak let-through show relative performance between designs; they are not part-number cross-references.
What is arc voltage in a fuse?
When a current-limiting fuse melts, the arc across the gap generates a voltage of its own, and it is that voltage which forces the current down. It can exceed the system voltage, which is why a current-limiting fuse cannot simply be applied at any voltage below its rating without checking — the surrounding insulation has to tolerate it.
How can I tell whether a fuse has operated?
By its indicator, where one is fitted. DENCO supplies several ranges with or without a visual trip indicator or microswitch, and PT fuses with a blown-fuse indicator on the 9F60 series. Without an indicator, an operated fuse often looks identical to a sound one, which is why the option matters on equipment that is inspected rather than monitored.
Can fuses be connected in parallel to get a higher rating?
Not as a field improvisation. Paralleling relies on the fuses sharing current equally, which two separately manufactured fuses will not reliably do, and the one carrying more will melt first. Where a higher rating is needed, the fuse itself is built with multiple elements — DENCO supplies double and triple barrel assemblies for exactly that reason.
What does non-venting mean on a fuse?
A non-venting fuse contains everything its operation produces inside the body, expelling no gas or material. DENCO's PT fuses are of this construction. It matters where the fuse sits in an enclosed compartment or close to other equipment, because a venting design needs clearance a non-venting one does not.
Cross-reference & replacement
Finding the DENCO equivalent of another manufacturer's fuse. Every equivalence below is one DENCO states in its own catalog — nothing here was derived by comparing specifications.
What is the DENCO equivalent of a GE 9F60 fuse?
DENCO's catalog states that its E-Rated Type EJ-1 is equivalent to the G.E. 9F60 series. That is DENCO's own published statement, quoted from page 49 of its January 2025 catalog, not a match we derived. The 9F60 series is now catalogued by Mersen, which is why buyers search under both names. Send the full 9F60 part number and DENCO will confirm the specific equivalent.
Does DENCO make a replacement for the GE CLF fuse?
Yes. DENCO's line card states that its DCLF can be substituted for GE CLF and Cooper ELSP designs. It is an oil-submersible current-limiting backup fuse for oil-filled distribution transformers. Send the CLF part number you are replacing and DENCO will confirm the DCLF equivalent against it.
What replaces a Cooper ELSP fuse?
DENCO's DCLF. The catalog's line card states that the DCLF can be substituted for GE CLF and Cooper ELSP designs. Cooper Power Systems was acquired by Eaton in 2012, so the same product is often searched for under Eaton or Bussmann — this is the row those searches are looking for.
What is the DENCO equivalent of a Cooper CBUC fuse?
DENCO's DEFTH. The catalog states that this fuse can be substituted for Cooper CBUC.., Hi-Tech HTSS.. and Mersen 9F59CCF.. designs. The trailing dots are DENCO's own notation for the series with any rating suffix, so the statement covers the series rather than one part number.
What replaces a Hi-Tech HTSS fuse?
DENCO's DEFTH. The catalog names Hi-Tech HTSS.. alongside Cooper CBUC.. and Mersen 9F59CCF.. as designs the DEFTH can be substituted for. Send the full HTSS part number with the transformer details and DENCO will confirm the rating.
What is the DENCO equivalent of a Mersen 9F59CCF fuse?
DENCO's DEFTH. The catalog's line card states the DEFTH can be substituted for Mersen 9F59CCF.. designs, along with Cooper CBUC.. and Hi-Tech HTSS... For the 9F60 series, the equivalent is DENCO's E-Rated Type EJ-1 instead — the two are different families, so the part number matters.
Does DENCO cross-reference Mersen fuses?
For two ranges it publishes the equivalence directly: the E-Rated Type EJ-1 against the G.E. 9F60 series, which Mersen now catalogues, and the DEFTH against Mersen 9F59CCF.. designs. For anything outside those, send the Mersen part number and DENCO will evaluate it rather than us inferring a match from specifications.
Does DENCO cross-reference Eaton or Bussmann fuses?
Indirectly, and the corporate history is the reason. DENCO's catalog names Cooper — Cooper Power Systems was acquired by Eaton in 2012, and Cooper Bussmann is now sold as Eaton's Bussmann series. So the published Cooper ELSP and Cooper CBUC equivalences are the rows an Eaton or Bussmann search is usually after. Send the current Eaton part number and DENCO will confirm.
Does DENCO cross-reference Littelfuse?
Not from published data. Littelfuse is not named anywhere in DENCO's 141-page catalog, so there is no DENCO statement to quote and we will not originate one by comparing specifications — on a fault-interrupting device that is not a safe inference. Send the Littelfuse part number to DENCO directly and it will be evaluated against the range.
Does DENCO cross-reference Ferraz Shawmut fuses?
Not as a published part-number equivalence. Ferraz Shawmut appears in DENCO's catalog only on a peak let-through comparison chart, which shows relative performance and does not state that any part replaces any other. Treating that chart as a cross-reference would be a misreading of it. Send the part number and DENCO will evaluate it.
Can DENCO cross-reference any manufacturer's fuse?
DENCO states in its catalog that it can cross-reference all major manufacturers. What is published on this site is narrower on purpose: only the equivalences DENCO writes down itself. For everything else the route is to send the part number, because an equivalence on a fault-interrupting device should come from the manufacturer rather than from a table someone assembled.
How do I request a cross-reference from DENCO?
Send the competitor part number exactly as it is printed on the fuse, the system voltage, the ampere rating, and the standard or approval you have to meet. A photograph of the existing fuse and its mounting is usually the fastest route of all, because it settles the barrel count, the mounting style and any striker or indicator fitting at a glance.
Why won't DENCO just publish a full cross-reference table for every brand?
Because a wrong equivalence on a fuse does not produce a returns ticket, it produces a device that fails to interrupt a fault. The equivalences published here are ones DENCO states in its own catalog and can stand behind. Anything beyond that is evaluated case by case against the actual application.
What does the .. mean in a part number like CBUC.. or HTSS..?
It is DENCO's own shorthand for the series with any rating suffix — CBUC.. means the CBUC series, whatever the rating code that follows. It is not truncated text and not a typing error. It matters when reading the cross-reference table, because the statement covers a whole series rather than one specific part.
A fuse fits my holder. Does that mean it is the right replacement?
No, and this is the single most expensive assumption in fuse replacement. Voltage rating, interrupting rating, melting characteristic, barrel count and any striker or microswitch provision all still have to match. A fuse that fits physically may let through more energy than the equipment can take, or fail to interrupt the available fault current at all.
Are E-rated fuses from different manufacturers interchangeable?
The E rating fixes the melting characteristic and nothing else. Voltage rating, interrupting rating, barrel count, overall length, clip or bolt centres, and any indicator requirement all still have to match, and a fuse that physically fits is not necessarily electrically equivalent. Send the part number or a photograph and DENCO will confirm against it rather than answer from a table.
Are R-rated fuses from different manufacturers interchangeable?
The R number fixes the melting characteristic under ANSI/IEEE C37.46, so a 6R from one maker melts to the same criterion as a 6R from another. Everything else still has to match — voltage class, interrupting rating, barrel count, mounting centres, and whether the starter relies on a striker pin to trip the contactor. Confirm the last of those before ordering.
The fuse I need to replace is obsolete. Can DENCO still supply it?
Obsolete competitor ranges are a large part of what DENCO is asked for, and the published equivalences cover several discontinued designs. Send the part number from the fuse body even if the original manufacturer no longer lists it — the marking, the mounting and the transformer or starter it came out of are usually enough to identify a current equivalent.
The label on my fuse is unreadable. How can I identify it?
Send a photograph of the fuse and its mounting along with what it protects — the transformer rating, the motor starter, or the panel it sits in — plus the system voltage. The physical envelope, the mounting centres and the application together narrow it down quickly, and DENCO would rather identify it from evidence than have you order against a guess.
What is a DCLF fuse?
DCLF is DENCO's oil-submersible current-limiting backup fuse for oil-filled distribution transformers. DENCO's catalog states it can be substituted for GE CLF and Cooper ELSP designs. As a backup fuse it works in series with a low-current interrupting device, typically a bay-o-net expulsion link.
What is a DEFTH fuse?
DEFTH is a DENCO oil-immersed transformer fuse that its catalog states can be substituted for Cooper CBUC.., Hi-Tech HTSS.. and Mersen 9F59CCF.. designs. It is used in oil-filled distribution transformers, generally alongside a bay-o-net expulsion link handling the low-current end.
What is an EJ-1 fuse?
EJ-1 is DENCO's E-rated fuse type, which its catalog states is equivalent to the G.E. 9F60 series. EJ-1 is a series name rather than an orderable part number — the specific part depends on the voltage class and ampere rating, so send those and DENCO will confirm the catalog number.
Is the 9F60 a GE or a Mersen part?
Both names are correct at different points in its history: the 9F60 series originated with G.E. and is now catalogued by Mersen, which is why buyers search under either. DENCO's catalog names the 9F60 on seventeen separate pages and states the E-Rated Type EJ-1 as its equivalent.
Why does DENCO's catalog name Cooper rather than Eaton?
Because the catalog records the design's name at the time the equivalence was established. Cooper Power Systems was acquired by Eaton in 2012 and Cooper Bussmann is now sold as the Eaton Bussmann series. That is corporate history, which is checkable — it is stated here as such, and never as an engineering equivalence in its own right.
How long does a cross-reference request take?
Send the part number through the quote form or by phone and DENCO will come back on the equivalence. If you need the fuse as well as the answer, note that DENCO's standard lead time is 30 days across all products, which Dennis confirmed in August 2026 — against an industry norm closer to 90.
Can I send a drawing or specification instead of a part number?
Yes. A drawing, a specification extract or a photograph of the installation all work, and for an unmarked or obsolete fuse they are often better than a part number. What DENCO needs to see is the electrical duty — voltage, current, available fault current — and the physical envelope it has to fit.
By application
Which DENCO family fits a given job. If your application is close to one of these but not identical, the difference usually matters more than the similarity — send the details.
Which fuse do I need to protect a distribution transformer?
E-rated fuses are the class built for primary protection of distribution transformers on medium-voltage systems. DENCO supplies them from 625V to 36kV, 0.5E to 400E. For an oil-filled transformer with an internal fuse pocket, the oil-immersed bay-o-net and backup range is the one to look at instead.
Which fuse protects a pad-mounted transformer?
Pad-mounted and other oil-filled distribution transformers usually take a bay-o-net fuse link, often with an oil-submersible current-limiting backup fuse in series behind it. The bay-o-net handles overloads and low-current faults; the backup fuse handles high fault currents the expulsion link cannot.
What fuse do I need for a medium-voltage motor starter?
R-rated fuses, which DENCO supplies at 2.5kV, 4.8kV and 7.2kV in ratings from 1R to 36R and in single, double and triple barrel forms. They give short-circuit protection only — the overload side is the relay's job — and they are selected against the motor's starting profile rather than its full-load current alone.
What fuse protects a medium-voltage soft starter?
R-rated fuses cover soft-starter as well as contactor-starter duty. The starting profile is what governs the selection, so send the motor rating, the starting method and the system voltage, and confirm whether the starter relies on a striker pin to trip the contactor on a single-phase operation.
What fuse do I use on a capacitor bank?
C-rated capacitor fuses, which DENCO supplies from 1000V to 38kV in ratings from 1C to 200C. They are built for capacitor duty specifically — switching inrush and outrush, harmonic current, and clearing a case fault fast enough to prevent rupture. A transformer fuse of the same ampere rating is not a substitute.
What fuse protects a potential transformer?
PT fuses — compact, non-venting ferrule fuses with a high interrupting rating, sized for the fraction of an ampere a PT primary actually draws. DENCO supplies them from 0.625kV up to 38kV in ratings from 0.25A to 5A. Their job is to protect the primary winding and clear an internal fault without damaging the switchgear around it.
What fuse do I need for a metering or relaying circuit?
Instrument transformer circuits take PT fuses. Because the burden is tiny, the fuse is rated in fractions of an ampere and its purpose is to isolate a fault in the instrument transformer rather than to carry load. Send the PT rating and the system voltage and DENCO will confirm the part.
What can replace an expulsion fuse in a cutout?
DENCO's DHS and DHHS current-limiting dropout fuses are offered as replacements for cutout expulsion fuse-links, at 15.5kV to 24kV and 1A to 80A. Unlike an expulsion link, a current-limiting fuse cuts the magnitude of the fault as well as its duration — which changes the let-through energy downstream equipment sees, so the change should be assessed rather than assumed.
What fuse is used in underground distribution?
For 25kV class underground distribution, DENCO supplies loadbreak elbow fuses — a current-limiting fuse built into a fused elbow with a load break disconnect. For the transformers on that network, the oil-immersed bay-o-net and backup range applies instead.
What is a bay-o-net fuse and when is one used?
A bay-o-net is a fuse link mounted in a holder that can be withdrawn from an oil-filled transformer under oil, so the fuse can be replaced without untanking. DENCO supplies both the holders and the links, with fault sensor currents of 10, 15, 25, 40, 65, 100 and 140A, usually alongside an oil-submersible backup fuse.
Which fuse protects a thyristor or a diode?
Ultra-rapid semiconductor fuses. DENCO supplies them in Form 101 cylindrical from 130V to 1500V and 1A to 2000A, in NH square body, and in ferrule cartridge sizes from 10x38 to 20x127mm. The selection is made on I²t let-through against the device's withstand, not on ampere rating.
What fuse do I need for a DC drive, UPS or inverter?
Ultra-rapid semiconductor fuses, which cover DC drives, UPS and inverter duty along with rectifiers and traction equipment. Interrupting ratings are 200kA AC and 100kA DC. Send the device you are protecting and its I²t withstand figure and DENCO will match the fuse against it.
What fuse protects an electrochemical rectifier?
Ultra-rapid semiconductor fuses, which DENCO lists for electrochemical rectifier duty specifically. These are high-current DC installations, so the ampere rating, the DC voltage and the available fault current all need to be stated together with the device's I²t withstand.
What fuse is used in rail and traction equipment?
DENCO's ultra-rapid semiconductor range covers heavy traction equipment. The company's own origins are in this sector — it was incorporated in 1988 as DenMar Transit Engineering. Send the duty and the device being protected and the selection will be made against the I²t.
What fuse do I need for a solar PV string?
gPV photovoltaic fuses, which DENCO supplies from 600VDC to 1500VDC with matching bases. They are full-range DC fuses characterised for photovoltaic duty — a PV string is a current-limited source at sustained DC voltage, which is not the condition an AC fuse is designed for.
What fuse goes in a solar combiner box?
gPV fuses with their matching bases — DENCO supplies both. Combiner boxes are where string fusing is normally done, so the fuse must be rated for the array's maximum system voltage and sized above the module short-circuit current with the code margin applied. The solar RFQ guide lists what to send.
What fuse is used in EV charging equipment?
DENCO's electric vehicle DC fuses — compact current-limiting designs at 500V, 700V, 1000V and 1500V DC, from 50A to 400A, with a 20kA interrupting rating. They cover high-voltage DC vehicle and charging applications, where the DC rating is the governing figure rather than any AC equivalent.
What fuse protects a network protector?
DENCO's network protector fuses — high breaking capacity fuses for protecting circuit breakers in underground distribution networks, rated to 600VAC maximum with a 200kA interrupting rating and ampere ratings from 800A to 3000A.
Which fuse do I need for switchgear built to German standards?
Type HH fuse-links for medium and high voltage, or NH square body fuses for low voltage. DENCO supplies Type HH at 7.2kV to 36kV and NH in sizes NH000 to NH5 to German, French and American standards and in press-pack form. State the switchgear make and the striker convention it expects.
Which fuse do I need for UK or British Standard switchgear?
BS88 fuses — semiconductor-type ultra-rapid fuses with high breaking capacity and low power dissipation, which DENCO supplies from 250V to 1000V and 2A to 600A, with interrupting ratings of 200kA and 300kA.
What fuse do I need for a wind turbine or battery storage system?
It depends on which part of the system. The DC side — battery strings, DC links — points to the DC ranges, while converter and inverter protection is semiconductor duty. Describe the system and the point you are protecting, with the DC voltage and available fault current, and DENCO will direct it to the right range.
What fuse is used for power factor correction equipment?
C-rated capacitor fuses. Power factor correction banks are capacitor duty, with the switching inrush and harmonic content that implies, so they take a fuse built for it. Send the bank's kVAr rating, the system voltage and the configuration.
Which DENCO fuse is used in utility distribution networks?
Several, depending on the point in the network: E-rated fuses for distribution transformer primaries, DHS and DHHS dropout fuses in cutouts, loadbreak elbow fuses for 25kV class underground, bay-o-net and backup fuses inside oil-filled transformers, and network protector fuses for protecting circuit breakers underground.
Which DENCO fuse suits an industrial plant with medium-voltage motors?
R-rated fuses for the motor circuits, E-rated fuses for the distribution transformers feeding them, and C-rated fuses on any power factor correction. If the plant also runs drives or rectifiers, the ultra-rapid semiconductor range covers those.
Does DENCO supply fuses for mining or heavy industry?
The medium-voltage motor, transformer and capacitor ranges cover the equipment these sites run, and the semiconductor range covers their drives and rectifiers. Environmental conditions matter in these installations though — ambient temperature, enclosure and altitude all affect a continuous rating, so state them with the enquiry.
What fuse do I need for a generator or genset installation?
It depends what you are protecting and at what voltage. Describe the installation — generator rating, system voltage, available fault current and what sits between the generator and the load — and DENCO will point you at the right range rather than guess from the word generator alone.
I don't know which family I need. Where do I start?
Start with what the fuse protects and at what voltage — a transformer, a motor, a capacitor bank, a rectifier, a PV string. That one answer usually selects the family. The products page lists all fourteen with what each is for, and the selection guide works through the numbers you will need.
Can one fuse family cover more than one application?
Some overlap — E-rated fuses appear in both transformer and PT contexts, and the 9F60 type reference runs across several ranges. But overlap in a designation is not interchangeability in an application. The duty the fuse was characterised for is what decides it, so confirm against the application rather than the family name.
Selecting & specifying
Choosing the right fuse for an application, and what DENCO needs from you to confirm it.
How do I select a medium-voltage fuse?
Start with four numbers: the system voltage, the continuous current, the available fault current, and what the fuse is protecting. Those decide the voltage class, the ampere or E rating, the interrupting rating and the melting characteristic. The physical envelope and mounting then narrow it to a part number. The selection guide works through it in order.
Medium-voltage fuse selection guideHave DENCO confirm a selection
What information does DENCO need to quote a fuse?
The part number if you have one, the system voltage, the ampere rating, and the standard or approval you must meet. If you are replacing an existing fuse, a photograph of it and its mounting is usually the fastest route, because it settles the barrel count, the mounting centres and any striker fitting at once.
How do I size a fuse for a distribution transformer?
The fuse has to carry the transformer's full-load current continuously, tolerate its inrush without melting, and clear a fault on the primary before the transformer is damaged — which means checking the fuse's curve against the transformer's withstand curve. E-rated fuses are the class built for this duty. Send the transformer's rating and the system voltage and DENCO will confirm.
How do I size a fuse for a medium-voltage motor?
R-rated fuses are selected against the motor's starting profile, not its full-load current alone, because the fuse must survive repeated starts without degrading while still clearing a short circuit. They provide short-circuit protection only — overload protection is the relay's job. A coordination study against your actual system data is the right basis for the choice.
How do I choose a fuse for a capacitor bank?
Capacitor duty is its own problem: the fuse has to carry continuous current with the harmonic content the bank draws, tolerate switching inrush and outrush, and clear a case fault fast enough to prevent rupture. C-rated fuses are built for it. Send the bank's kVAr, the system voltage and the configuration and DENCO will confirm the part.
How do I choose a fuse to protect a thyristor or rectifier?
The governing number is I²t. The fuse's let-through I²t must be less than the semiconductor's withstand I²t, at the actual circuit voltage and with the actual fault current available. Ampere rating alone will not tell you this. Send the device's I²t withstand figure with the circuit details and DENCO will match against it.
How do I size a fuse for a solar PV string?
PV strings are a DC application with a current source that barely exceeds its rated output under fault, so the fuse must be a full-range gPV type rated for the string's maximum system voltage and sized above the module's short-circuit current with the code margin applied. The solar RFQ guide lists exactly what to send.
Does DENCO provide time-current curves?
Curves are held against the product families and are supplied with a quotation or on request. If you are carrying out a coordination study, say so when you enquire and state which curves you need — minimum melt, total clearing, or both — so the right ones come back the first time.
Does DENCO provide I²t let-through data?
Let-through data is what semiconductor protection is selected on, so it is supplied with a quotation for those ranges. Send the device you are protecting and its I²t withstand and DENCO will confirm the fuse against it rather than leave the comparison to be made from a datasheet alone.
Can DENCO help with a coordination study?
Send the system data — voltages, available fault current, the devices upstream and downstream, and what you are protecting — and DENCO will advise on fuse selection against it. The study itself is engineering work on your system; what DENCO provides is the fuse characteristics it has to be done with, and a recommendation against them.
What voltage rating should I choose?
The fuse's maximum design voltage must be at least the system's maximum operating voltage, not its nominal. A 4.16kV nominal system is normally served by a 4.8kV class fuse for that reason. Going higher than necessary is not automatically safe either, because current-limiting performance is characterised at the rating — state the system voltage and let DENCO confirm.
What if my available fault current exceeds the fuse's interrupting rating?
Then the fuse must not be used at that point in the system. An interrupting rating is a limit, not a guideline, and exceeding it risks the fuse failing to clear. Either a higher-rated fuse or a change in the system design is needed. Send your fault study figure with the enquiry so this is checked before anything is quoted.
Can I use a higher ampere rating than the original fuse?
Not as a way of stopping nuisance operation. The original rating was chosen to protect something, and raising it moves the protection away from what it was set to. If a fuse is operating unexpectedly the cause is worth finding first — inrush, harmonics, a developing fault or a coordination error all look the same from the fuse holder.
My fuse keeps blowing. What should I check?
Repeated operation is a symptom, not a fault in the fuse. The usual causes are inrush the fuse was never sized for, harmonic content raising the RMS current above what the nameplate suggests, a developing fault in the protected equipment, or a coordination error putting the wrong device nearest the problem. Send the application details and DENCO will look at the selection with you.
Do I need a fuse with a striker pin?
You need one if the equipment relies on it. In many medium-voltage starters the striker mechanically trips the contactor so that all three phases open when a single fuse operates — without it, the installation can be left single-phasing. Check what the existing fuse has, and say so when you enquire.
What is the difference between an E-rated and an R-rated fuse?
They are different melting criteria for different duties. E-rated fuses protect transformers and are defined by ANSI/IEEE C37.46's 300-second and 600-second criteria. R-rated fuses protect motor circuits and must melt in 15 to 35 seconds at 100 times the R number. They are not substitutes: an E-rated fuse in a motor starter will not survive the starting duty the R rating exists for.
What is the difference between a C-rated and an E-rated fuse?
C-rated fuses are for capacitor duty and E-rated fuses for transformer duty, and the difference is what they have to tolerate. A capacitor fuse must handle switching inrush and outrush and the harmonic current a bank draws, and clear a case fault fast enough to prevent rupture. A transformer fuse is matched to inrush and to the transformer's withstand curve instead.
What is the difference between a PT fuse and an E-rated transformer fuse?
Scale and purpose. A potential transformer is an instrument transformer presenting a voltage to metering or relaying, so its primary draws a fraction of an ampere and the fuse is sized to that. An E-rated transformer fuse protects a power transformer carrying load. Both may meet E-rating criteria, but they are not interchangeable in either direction.
What is the difference between BS88 and NH fuses?
They are two national traditions for the same job. BS88 is the British Standard series; NH is the German square-body knife-blade series, sized NH000 to NH5. The bodies, the mounting and the standards differ, so they are not interchangeable, and which one an installation takes is usually decided by where the switchgear was designed.
What is the difference between a Type HH fuse and a North American E-rated fuse?
Type HH is the German-style HRC current-limiting fuse-link for medium and high voltage distribution; E-rated fuses are the North American equivalent duty defined by ANSI/IEEE C37.46. The standards, the dimensions and the striker conventions differ. Which you need follows the switchgear, so state what the fuse is going into.
Should I use a current-limiting dropout fuse or an expulsion cutout link?
A current-limiting dropout fuse reduces the let-through energy a fault delivers to the rest of the installation, which an expulsion link does not. That is the reason to change. But the change alters what downstream equipment experiences and the coordination around it, so it should be assessed rather than swapped in on the basis that it fits the same cutout.
Do I need a fuse or a circuit breaker?
They are not alternatives so much as different instruments. A current-limiting fuse clears a high fault current faster than a breaker can open, and limits the energy let through in doing so; a breaker is resettable and can be controlled and coordinated electrically. Many medium-voltage installations use both, with the fuse handling the short-circuit end.
Can DENCO supply a fuse to a custom specification?
DENCO manufactures fuses and its engineering team has, by its own account, over 100 years of combined experience solely in manufacturing electrical fuses. Send the electrical duty and the physical envelope you need and it will come back on whether it can be built. Special and non-standard requirements are a normal part of the enquiry mix rather than an exception.
What is the DENCO part numbering system?
Catalog numbers encode the voltage class and the rating — D5.5F1-100E, for example, carries the 5.5kV class, a barrel configuration and a 100E rating. The pattern varies by family, so rather than decode it yourself, send the number you have and DENCO will identify it. The catalog's spec tables list the numbers against their ratings family by family.
Which dimensions matter when replacing a fuse?
Overall length, body diameter, and then the mounting dimension — clip centre distance for a clip-mounted fuse, bolt centre distance for a bolt-in. The catalog publishes these as dimension columns against each catalog number. Barrel count matters too, because it changes the envelope even where the electrical ratings match.
Does DENCO supply fuse bases, holders and mountings?
Yes for several ranges — gPV photovoltaic fuses are supplied with matching bases, NH square body fuses with bases, and bay-o-net fuse holders are part of the oil-immersed range. Say what mounting you need with the fuse enquiry so the pair is quoted together.
Is a fuse that meets a standard the same as one certified to it?
No, and the wording is deliberate throughout this site. Designed to, in accordance with, conforms to, tested to, certified and listed are different strengths of evidence and are never used interchangeably here. Where DENCO's standards evidence is still being confirmed, the site says designed to rather than upgrade the claim. Ask for the specific evidence you need and it will be answered directly.
Is DENCO ISO 9001 certified?
DENCO's fuses are manufactured under an ISO 9001:2015 quality system. The certificate is held by DENCO's manufacturing partner rather than by DENCO itself, which is a distinction worth stating plainly rather than blurring. If your specification requires certification evidence, ask and DENCO will tell you exactly what can be provided.
Can I get a datasheet for a DENCO fuse?
Request the product catalog, which carries the specification tables, dimensions and ratings family by family, and ask for the specific part number you need. If you require a controlled datasheet for a submittal, say so — the requirement is different from a catalog extract and DENCO will confirm what it can issue.
Can DENCO advise if I am not sure what I need?
Yes, and it is the normal way these enquiries start. Describe what the fuse is protecting, the system voltage and what went wrong if something did. DENCO would rather work from the application than have you order against a guess, and a photograph of the existing installation is often worth more than a part number.
Catalog, part numbers & documentation
Reading a DENCO part number, and getting the paperwork an installation or a submittal needs.
How do I read a DENCO catalog number?
The number encodes the voltage class and the rating — in D5.5F1-100E, the 5.5 is the kV class, the F1 the barrel configuration and the 100E the rating. The pattern varies between families, so rather than decode it, send the number you have and DENCO will identify it against the range.
What does the E suffix on a DENCO part number mean?
It marks the rating as an E rating — a melting characteristic defined by ANSI/IEEE C37.46, rather than a plain ampere figure. A 100E fuse must melt within 300 seconds at between 200% and 240% of its rating, because it sits below the 100 A threshold in the standard.
What does the C suffix on a DENCO capacitor fuse mean?
It marks a C rating — the capacitor-duty melting characteristic. DENCO's C-rated fuses are published as melting in 1000 seconds at 1.7 to 2.4 times the C rating, which is a slower, higher-multiple criterion than the E rating, matched to what a capacitor bank actually does in service.
Why do some DENCO part tables say DENMAR Order #?
Because the company was incorporated in 1988 as DenMar Transit Engineering and has also traded as DenMar Fuses. Some catalog pages still carry the older heading while others say DENCO Order #. It is the same ordering reference — if a table you are reading uses one and a neighbouring page the other, that is history rather than two different numbers.
Is the product code DNX or DM NX?
DNX, and DNXC for the related variant. These are the designations used throughout the capacitor fuse product tables. A DM NX reading comes from a marketing line rather than the product data, and the tables are the authority.
What is in the DENCO catalog?
141 pages covering the full range family by family — specification tables, catalog numbers, dimensions, ratings and curves. It is the document most technical enquiries end up needing, and it can be requested from the catalog page.
How do I get a copy of the DENCO catalog?
Request it from the catalog page on this site. If you already know which family you need, say so — the relevant specification tables can be pointed out directly rather than leaving you to find them across 141 pages.
Are the ratings in the catalog published on this website?
Part numbers are listed on each family page. The per-part ratings read out of the catalog's specification tables — ampere rating, maximum voltage, interrupting rating and dimensions — are prepared but not yet published here, because they are engineering claims awaiting DENCO's sign-off. Ask for the ratings you need and they will be supplied against the part.
How many part numbers does DENCO list?
Several hundred across the range, concentrated in the E-rated, semiconductor, PT, R-rated and capacitor families. DENCO confirmed in August 2026 that all catalog part numbers are current, other than the withdrawn UL classes which have left the range entirely.
Can I get a dimensional drawing for a DENCO fuse?
The catalog carries dimension columns and figure references for each family — overall length, diameter, clip centre and bolt centre as applicable. If you need a drawing for a submittal rather than a catalog extract, say so when you ask, because that is a different document.
Can I get a time-current curve for a specific part number?
Yes — say which part number and whether you need minimum melt, total clearing or both. If it is for a coordination study, mention that too, along with the devices you are coordinating against, so the right curves come back the first time.
Does DENCO publish I²t let-through curves?
Let-through data is what semiconductor and PV selections are made on, and it is supplied with a quotation for those ranges. The loadbreak elbow range additionally publishes an I²t correction curve and a watts-loss correction curve alongside its time-current curve.
Can I get test reports or certification documents?
Ask for the specific evidence your specification requires and DENCO will tell you what it can issue. The site is deliberately careful here: designed to, conforms to, tested to and certified are different claims, and none is presented as another.
What is the manufacturing date on a DENCO fuse label?
PT fuses carry the catalog number and the manufacturing date on an affixed label. If you are identifying an installed fuse, that label is the best starting point — send a photograph of it with the enquiry.
Is there a DENCO part number for a fuse base or holder?
Yes for the ranges supplied with them — NH square body bases are listed 2 to 2000A at 690V, gPV fuses have matching bases, and bay-o-net holders are part of the oil-immersed range. Quote the fuse and the base together so the pair is matched.
I found a discrepancy in the DENCO catalog. Who do I tell?
Get in touch with the page and the part number. A published catalog of this size carries the occasional inconsistency — a rating printed twice differently, or a column heading that does not match its neighbours — and DENCO would rather hear about it than have someone specify from it.
Where can I find DENCO's full product range?
The products page lists all fourteen families with what each is for, grouped into medium and high voltage, international BS88 and NH and Type HH ranges, semiconductor protection, and renewable energy and special purpose. Each family has its own page with specifications and part numbers.
Does this website list every DENCO product?
It lists the fourteen current families and their published specifications. The catalog goes further into per-part detail, and some ranges — special and custom builds in particular — are handled by enquiry rather than being catalogued. If you cannot find what you are looking for, ask rather than assume it is not made.
Ordering, delivery & the company
How to buy from DENCO, and who DENCO is.
Who is DENCO Fuses?
DENCO Fuses, Inc. is a manufacturer of medium and high voltage fuses based in Miami, Florida. It was incorporated in Florida in 1988 as DenMar Transit Engineering, and has also traded as DenMar Fuses. Its range covers transformer, motor, capacitor, potential transformer, semiconductor, solar and DC applications.
Where is DENCO located?
DENCO Fuses is at 8244 SW 103 Ave, Miami, Florida 33173, in the United States. Enquiries are handled from there by phone, email or the quote form on this site.
How do I contact DENCO?
By phone on (305) 273-6226, toll-free on 1-800-305-FUSE (3873), or through the quote form on the contact page. The direct line is answered during US Eastern business hours, Monday to Friday. For a technical enquiry the form is often quicker, because you can attach a photograph or a specification.
What are DENCO's business hours?
The office line is answered 8am to 5pm US Eastern time, Monday to Friday. Enquiries sent through the quote form outside those hours are picked up the next working day.
What is DENCO's lead time?
30 days, and it applies across all products. DENCO confirmed this in August 2026. For context, the industry norm for medium-voltage fuses of this kind is closer to 90 days. If you have a shorter requirement, say so with the enquiry rather than after the order.
How do I request a quote from DENCO?
Use the quote form on the contact page. Send the part number if you have one, the system voltage, the ampere rating and the standard or approval you must meet — and a photograph of the existing fuse and its mounting if you are replacing one, which usually settles the physical details faster than a description.
Does DENCO sell direct or through distributors?
DENCO works with distributors as well as taking enquiries directly. If you are a distributor interested in carrying the range, the contact page has the distributor application; if you are an end user, send your enquiry through the quote form and DENCO will route it appropriately.
How do I become a DENCO distributor?
There is a distributor application on the contact page. Download it, complete it and return it, or get in touch first if you would rather discuss the territory and the range before applying.
Does DENCO ship to Canada?
Yes. DENCO supplies the United States and Canada, and handles export enquiries beyond North America. Include the delivery country with your enquiry so shipping and any documentation requirements are quoted with the fuses.
Does DENCO export outside North America?
Yes — export is part of the business alongside the US and Canada. DENCO's range includes BS88, NH square body and Type HH fuses built to British, German, French and IEC practice, so international requirements are familiar ground. State the destination and the standard you need to meet.
Is there a minimum order quantity?
Send the quantity you need with the enquiry and DENCO will quote against it. Requirements range from a single replacement fuse to production quantities, and both are normal.
Can I get a copy of the DENCO catalog?
Yes — request it from the catalog page. It runs to 141 pages and carries the specification tables, dimensions and ratings for the full range, family by family, which is the document most technical enquiries end up needing.
How long has DENCO been making fuses?
The company was incorporated in Florida in 1988, as DenMar Transit Engineering. Its engineering team has over 100 years of combined experience, solely in manufacturing electrical fuses — the scope of that figure is part of the claim, not decoration.
Was DENCO previously called something else?
Yes. The company was incorporated in 1988 as DenMar Transit Engineering, Inc., and has also traded as DenMar Fuses, Inc. Older equipment and paperwork may carry either name, and some catalog part tables are still headed DENMAR Order # for that reason.
Does DENCO manufacture its own fuses?
DENCO is a fuse manufacturer, and its products are made under an ISO 9001:2015 quality system. The certificate for that system is held by DENCO's manufacturing partner rather than by DENCO itself — a distinction stated plainly here rather than blurred into a claim DENCO cannot make.
What industries does DENCO supply?
Electric utilities and distribution, industrial plant with medium-voltage motors, capacitor and power-factor installations, rail and traction, solar and renewable generation, electric vehicle charging, and the electrochemical and drives sectors through its semiconductor range.
What products does DENCO make?
Fourteen families across four groups: medium and high voltage fuses for transformers, motors, capacitors, potential transformers, dropout applications, loadbreak elbows and oil-immersed transformers; international ranges in BS88, NH square body and Type HH; ultra-rapid semiconductor fuses; and renewable-energy ranges for solar PV and electric vehicle DC, plus network protector fuses.
Does DENCO still supply Class J, RK1, RK5 or K5 fuses?
No. Those UL classes were withdrawn from the range in 2026 and are no longer offered. If you have been supplied one historically, get in touch with the part number and DENCO will advise on what is available now.
Are all the part numbers in the DENCO catalog still available?
Yes — DENCO confirmed in August 2026 that all catalog part numbers are current, with the exception of the withdrawn UL classes, which are no longer in the range at all. If a number you hold is not in the current catalog, send it over and it will be identified.
Can DENCO supply an obsolete or discontinued fuse?
Obsolete competitor ranges are a substantial part of what DENCO is asked for, and several published equivalences cover discontinued designs. Send the part number from the fuse body, even if the original maker no longer lists it, along with what it protects.
Does DENCO offer technical support after purchase?
Yes. If a fuse is operating unexpectedly, or a replacement is not behaving as the one it replaced did, get in touch with the application details. Repeated operation is usually telling you something about the installation rather than about the fuse, and it is worth investigating properly.
Who do I speak to about a technical question?
Call the office line on (305) 273-6226 during US Eastern business hours and ask for technical, or send the question through the quote form with as much application detail as you can. Technical enquiries are answered by DENCO's own engineering people rather than passed to a call centre.
Can I visit DENCO?
DENCO is based at 8244 SW 103 Ave, Miami, Florida. Arrange any visit in advance by phone or through the contact form rather than calling in — it means the right person is there when you arrive.
Does DENCO have a UK or European office?
DENCO operates from Miami, Florida and supplies international customers by export. Its range includes BS88, NH square body and Type HH fuses built to British, German, French and IEC practice, so European specifications are handled routinely — but the point of contact is the Miami office.
Medium & high voltage fuses
Transformer, motor, capacitor, PT, dropout, elbow and oil-immersed ranges.
What are DENCO E-rated fuses?
DENCO E-rated fuses provide primary protection for distribution transformers on medium-voltage systems. They are current-limiting, supplied in the 9F60/EJ-1, 9F62/EJO-1 and Clip Lock 14 series, with or without a visual trip indicator or microswitch, in clip-on, bolt-on, clip-lock and custom mountings.
What voltage ratings are DENCO E-rated fuses available in?
DENCO E-rated fuses are supplied at 625V, 1500V, 2.75kV, 5.5kV, 8.25kV, 12kV, 15.5kV, 24kV, 25.8kV, 36kV. The fuse’s maximum design voltage must be at least your system’s maximum operating voltage, not its nominal, so confirm the system figure when you enquire.
What is the highest voltage DENCO E-rated fuses are available in?
36kV is the top of the published range, which runs 625V, 1500V, 2.75kV, 5.5kV, 8.25kV, 12kV, 15.5kV, 24kV, 25.8kV, 36kV. If your application sits above that, send the details — this is the catalog range, not the limit of what DENCO can discuss.
E-Rated Transformer Protection FusesAsk about a special requirement
What ampere ratings do DENCO E-rated fuses cover?
The published range is 0.5E to 400E (0.5A to 400A). Rating is only part of the selection: the melting characteristic, the interrupting rating and the physical envelope all have to match the application as well.
What is the interrupting rating of DENCO E-rated fuses?
31kA, 38kA, 50kA, 60kA, 63kA, 80kA, 82kA, 100kA, 120kA. An interrupting rating is a limit rather than a guideline — the fuse must not be applied where the available fault current exceeds it, so check the figure against your system’s fault study.
E-Rated Transformer Protection FusesCheck against your fault current
What are DENCO E-rated fuses used for?
General purpose transformer protection, power distribution fuse duty, main and back-up protection designs and indoor or outdoor within an enclosure. If your application is close to one of these but not quite the same, describe it when you enquire — the difference usually matters more than the similarity.
E-Rated Transformer Protection FusesDescribe your application
What are the application limits for DENCO E-rated fuses?
Enclosure required for outdoor installation and final selection requires DENCO engineering review. Limits like these are stated deliberately: a fuse applied outside what it was characterised for can fit, energise and still fail to protect.
What standards do DENCO E-rated fuses follow?
They are designed to ANSI C37. The wording matters and is not decoration: designed to, conforms to, tested to and certified are different strengths of evidence, and this site does not upgrade one into another. If your specification needs a particular level of evidence, ask and DENCO will answer it directly.
E-Rated Transformer Protection FusesAsk about standards evidence
How are DENCO E-rated fuses mounted?
Clip-on, bolt-on with brackets, clip-lock, or custom mounting designs. Mounting style is not interchangeable even where the electrical ratings match, so clip centres or bolt centres need to be confirmed against the existing installation.
Are DENCO E-rated fuses available with a blown-fuse indicator?
With or without visual trip indicator or microswitch. Where the equipment relies on an indicator or a striker to trip a contactor, the replacement must carry the same provision — a fuse that is electrically correct but lacks it will leave that function missing.
E-Rated Transformer Protection FusesSpecify the indicator option
What series or type designations do DENCO E-rated fuses carry?
9F60, 9F62 Series, EJ-1, EJO-1 and Standard. These are the designations to quote when identifying an existing fuse, and several of them are the names buyers search for rather than the DENCO catalog number itself.
How many DENCO E-rated fuses part numbers are there?
The catalog lists 342 catalog numbers for this family, across pp.25-44. DENCO confirmed in August 2026 that all catalog part numbers are current. Send the number you hold and it will be identified against the range.
How do I request a quote for DENCO E-rated fuses?
Send the part number if you have one, the system voltage, the ampere rating and the standard you must meet, through the quote form. If you are replacing an existing fuse, a photograph of it and its mounting settles the physical details faster than a description. DENCO’s standard lead time is 30 days across all products.
What are DENCO PT fuses?
DENCO PT fuses are high-interrupting, current-limiting fuses designed to protect the primary windings of potential transformers. They are compact ferrule-type fuses that fit standard mounting clips, are non-venting for quiet operation, and carry a blown-fuse indicator on the 9F60 series.
What voltage ratings are DENCO PT fuses available in?
DENCO PT fuses are supplied at 0.625kV, 2.4kV, 2.75kV, 4.8kV, 5.0kV, 5.5kV, 7.2kV, 8.25kV and 15.5kV. The fuse’s maximum design voltage must be at least your system’s maximum operating voltage, not its nominal, so confirm the system figure when you enquire.
What is the highest voltage DENCO PT fuses are available in?
15.5kV is the top of the published range, which runs 0.625kV, 2.4kV, 2.75kV, 4.8kV, 5.0kV, 5.5kV, 7.2kV, 8.25kV and 15.5kV. If your application sits above that, send the details — this is the catalog range, not the limit of what DENCO can discuss.
Potential Transformer (PT) Protection FusesAsk about a special requirement
What ampere ratings do DENCO PT fuses cover?
The published range is 0.25A to 5A. Rating is only part of the selection: the melting characteristic, the interrupting rating and the physical envelope all have to match the application as well.
What is the interrupting rating of DENCO PT fuses?
50kA, 52kA, 63kA, 80kA, 100kA and 120kA RMS symmetrical. An interrupting rating is a limit rather than a guideline — the fuse must not be applied where the available fault current exceeds it, so check the figure against your system’s fault study.
Potential Transformer (PT) Protection FusesCheck against your fault current
What are DENCO PT fuses used for?
Potential transformer primary winding protection; protection for 0.625kV to 15.5kV transformers or distribution systems; indoor or enclosure-mounted switchgear. If your application is close to one of these but not quite the same, describe it when you enquire — the difference usually matters more than the similarity.
Potential Transformer (PT) Protection FusesDescribe your application
How are DENCO PT fuses mounted?
Cylindrical clip-on, compatible with standard clips; clip-mounted and clip-lock variants. Mounting style is not interchangeable even where the electrical ratings match, so clip centres or bolt centres need to be confirmed against the existing installation.
Potential Transformer (PT) Protection FusesConfirm the mounting
Are DENCO PT fuses available with a blown-fuse indicator?
Blown-fuse indicator on the 9F60 series; open fuse trip indicator, trip length 0.25 in. Where the equipment relies on an indicator or a striker to trip a contactor, the replacement must carry the same provision — a fuse that is electrically correct but lacks it will leave that function missing.
Potential Transformer (PT) Protection FusesSpecify the indicator option
How are DENCO PT fuses constructed?
Compact ferrule type, non-venting, with catalog number and manufacturing date on an affixed label. Construction detail matters when a fuse has to fit an existing holder, so confirm the envelope against the installation rather than the description alone.
What series or type designations do DENCO PT fuses carry?
9F60 Series, EJ-1; types DAAA, DBBB, D24T, D48T, D50T, D72T, DBDE, DBHH. These are the designations to quote when identifying an existing fuse, and several of them are the names buyers search for rather than the DENCO catalog number itself.
Potential Transformer (PT) Protection FusesCross-reference table
How many DENCO PT fuses part numbers are there?
The catalog lists 52 catalog numbers for this family, across pp.45-50. DENCO confirmed in August 2026 that all catalog part numbers are current. Send the number you hold and it will be identified against the range.
Potential Transformer (PT) Protection FusesRequest the catalog
How do I request a quote for DENCO PT fuses?
Send the part number if you have one, the system voltage, the ampere rating and the standard you must meet, through the quote form. If you are replacing an existing fuse, a photograph of it and its mounting settles the physical details faster than a description. DENCO’s standard lead time is 30 days across all products.
What are DENCO DHS and DHHS dropout fuses?
DENCO DHS and DHHS current-limiting dropout fuses are offered as replacements for cutout expulsion fuse-links. Unlike an expulsion fuse, a current-limiting fuse interrupts without expelling gas and limits the let-through fault current.
What voltage ratings are DENCO DHS and DHHS dropout fuses available in?
DENCO DHS and DHHS dropout fuses are supplied at 15.5kV to 24kV. The fuse’s maximum design voltage must be at least your system’s maximum operating voltage, not its nominal, so confirm the system figure when you enquire.
What ampere ratings do DENCO DHS and DHHS dropout fuses cover?
The published range is 1A to 80A. Rating is only part of the selection: the melting characteristic, the interrupting rating and the physical envelope all have to match the application as well.
What are DENCO DHS and DHHS dropout fuses used for?
Replacement for cutout expulsion fuse-links and overhead distribution protection. If your application is close to one of these but not quite the same, describe it when you enquire — the difference usually matters more than the similarity.
DHS & DHHS Current-Limiting Dropout FusesDescribe your application
What are the application limits for DENCO DHS and DHHS dropout fuses?
Replacement suitability requires DENCO review of the existing installation. Limits like these are stated deliberately: a fuse applied outside what it was characterised for can fit, energise and still fail to protect.
What standards do DENCO DHS and DHHS dropout fuses follow?
They are conform to NBR 8124, IEC 60282-2 and ANSI / ABNT. The wording matters and is not decoration: designed to, conforms to, tested to and certified are different strengths of evidence, and this site does not upgrade one into another. If your specification needs a particular level of evidence, ask and DENCO will answer it directly.
DHS & DHHS Current-Limiting Dropout FusesAsk about standards evidence
Where are DENCO DHS and DHHS dropout fuses covered in the catalog?
Pp.51-52 of DENCO’s January 2025 catalog. Request a copy and the specification tables, dimensions and ratings for this family come with it.
DHS & DHHS Current-Limiting Dropout FusesRequest the catalog
How do I request a quote for DENCO DHS and DHHS dropout fuses?
Send the part number if you have one, the system voltage, the ampere rating and the standard you must meet, through the quote form. If you are replacing an existing fuse, a photograph of it and its mounting settles the physical details faster than a description. DENCO’s standard lead time is 30 days across all products.
What are DENCO R-rated fuses?
DENCO R-rated fuses provide short-circuit protection for medium-voltage motor starters and soft starters. They are current-limiting with a high interrupting rating and are supplied in single, double and triple barrel configurations.
What voltage ratings are DENCO R-rated fuses available in?
DENCO R-rated fuses are supplied at 2.5kV, 4.8kV, 7.2kV. The fuse’s maximum design voltage must be at least your system’s maximum operating voltage, not its nominal, so confirm the system figure when you enquire.
What is the highest voltage DENCO R-rated fuses are available in?
7.2kV is the top of the published range, which runs 2.5kV, 4.8kV, 7.2kV. If your application sits above that, send the details — this is the catalog range, not the limit of what DENCO can discuss.
R-Rated Motor & Soft-Starter FusesAsk about a special requirement
What ampere ratings do DENCO R-rated fuses cover?
The published range is 1R, 2R, 3R, 4R, 5R, 6R, 9R, 12R, 18R, 24R, 36R. Rating is only part of the selection: the melting characteristic, the interrupting rating and the physical envelope all have to match the application as well.
What is the interrupting rating of DENCO R-rated fuses?
RMS symmetrical 63kA and 65kA; RMS asymmetrical 100kA. An interrupting rating is a limit rather than a guideline — the fuse must not be applied where the available fault current exceeds it, so check the figure against your system’s fault study.
R-Rated Motor & Soft-Starter FusesCheck against your fault current
What are DENCO R-rated fuses used for?
Medium-voltage motor protection, motor starter and controller protection and motor circuit protection. If your application is close to one of these but not quite the same, describe it when you enquire — the difference usually matters more than the similarity.
What are the application limits for DENCO R-rated fuses?
Short-circuit protection only — not overload protection; coordination study required; see the selection guide. Limits like these are stated deliberately: a fuse applied outside what it was characterised for can fit, energise and still fail to protect.
What standards do DENCO R-rated fuses follow?
They are designed to DIN 43625, IEC 282-1 and BS 2692. The wording matters and is not decoration: designed to, conforms to, tested to and certified are different strengths of evidence, and this site does not upgrade one into another. If your specification needs a particular level of evidence, ask and DENCO will answer it directly.
R-Rated Motor & Soft-Starter FusesAsk about standards evidence
What is the melting characteristic of DENCO R-rated fuses?
Melts in 15 to 35 seconds at 100x the R rating. Melting time is not clearing time — clearing adds the arcing time needed to actually interrupt the circuit, so a total-clearing figure is always the longer of the two.
R-Rated Motor & Soft-Starter FusesTime-current curves and I²t
What configurations are DENCO R-rated fuses available in?
Single, double and triple barrel. The physical envelope has to match the holder as well as the electrical duty, so send the mounting details or a photograph with your enquiry.
How many DENCO R-rated fuses part numbers are there?
The catalog lists 39 catalog numbers for this family, across pp.53-58. DENCO confirmed in August 2026 that all catalog part numbers are current. Send the number you hold and it will be identified against the range.
How do I request a quote for DENCO R-rated fuses?
Send the part number if you have one, the system voltage, the ampere rating and the standard you must meet, through the quote form. If you are replacing an existing fuse, a photograph of it and its mounting settles the physical details faster than a description. DENCO’s standard lead time is 30 days across all products.
What are DENCO C-rated capacitor fuses?
DENCO C-rated fuses protect capacitors and capacitor banks against case rupture and dielectric failure. They are current-limiting with silent operation and no discharge, and are available with or without a blown-fuse indicator.
What voltage ratings are DENCO C-rated capacitor fuses available in?
DENCO C-rated capacitor fuses are supplied at 1000V, 1.5kV, 2.5kV, 3kV, 4.3kV, 5.5kV, 8.3kV, 15.5kV, 23kV, 27kV, 38kV. The fuse’s maximum design voltage must be at least your system’s maximum operating voltage, not its nominal, so confirm the system figure when you enquire.
What is the highest voltage DENCO C-rated capacitor fuses are available in?
38kV is the top of the published range, which runs 1000V, 1.5kV, 2.5kV, 3kV, 4.3kV, 5.5kV, 8.3kV, 15.5kV, 23kV, 27kV, 38kV. If your application sits above that, send the details — this is the catalog range, not the limit of what DENCO can discuss.
C-Rated Capacitor Protection FusesAsk about a special requirement
What ampere ratings do DENCO C-rated capacitor fuses cover?
The published range is 1C to 200C (1A to 200A). Rating is only part of the selection: the melting characteristic, the interrupting rating and the physical envelope all have to match the application as well.
What is the interrupting rating of DENCO C-rated capacitor fuses?
40kA, 50kA, 60kA, 65kA, 80kA. An interrupting rating is a limit rather than a guideline — the fuse must not be applied where the available fault current exceeds it, so check the figure against your system’s fault study.
C-Rated Capacitor Protection FusesCheck against your fault current
What are DENCO C-rated capacitor fuses used for?
Capacitor and capacitor bank protection, power factor correction equipment, harmonic filtering equipment, induction heating systems and high power drives and welders. If your application is close to one of these but not quite the same, describe it when you enquire — the difference usually matters more than the similarity.
What are the application limits for DENCO C-rated capacitor fuses?
Indoor or outdoor within an enclosure. Limits like these are stated deliberately: a fuse applied outside what it was characterised for can fit, energise and still fail to protect.
What standards do DENCO C-rated capacitor fuses follow?
They are designed to ANSI C37-41. The wording matters and is not decoration: designed to, conforms to, tested to and certified are different strengths of evidence, and this site does not upgrade one into another. If your specification needs a particular level of evidence, ask and DENCO will answer it directly.
C-Rated Capacitor Protection FusesAsk about standards evidence
What is the melting characteristic of DENCO C-rated capacitor fuses?
Melts in 1000 seconds at 1.7 to 2.4x the C rating. Melting time is not clearing time — clearing adds the arcing time needed to actually interrupt the circuit, so a total-clearing figure is always the longer of the two.
C-Rated Capacitor Protection FusesTime-current curves and I²t
Are DENCO C-rated capacitor fuses available with a blown-fuse indicator?
With or without blown fuse indicator. Where the equipment relies on an indicator or a striker to trip a contactor, the replacement must carry the same provision — a fuse that is electrically correct but lacks it will leave that function missing.
C-Rated Capacitor Protection FusesSpecify the indicator option
What series or type designations do DENCO C-rated capacitor fuses carry?
DNX / DNXC, 9F60 Series, EJ-5, EJO-5 and Standard. These are the designations to quote when identifying an existing fuse, and several of them are the names buyers search for rather than the DENCO catalog number itself.
How many DENCO C-rated capacitor fuses part numbers are there?
The catalog lists 17 catalog numbers for this family, across pp.59-75. DENCO confirmed in August 2026 that all catalog part numbers are current. Send the number you hold and it will be identified against the range.
How do I request a quote for DENCO C-rated capacitor fuses?
Send the part number if you have one, the system voltage, the ampere rating and the standard you must meet, through the quote form. If you are replacing an existing fuse, a photograph of it and its mounting settles the physical details faster than a description. DENCO’s standard lead time is 30 days across all products.
What are DENCO loadbreak elbow fuses?
DENCO loadbreak elbow fuses are current-limiting fuses built into a fused elbow for 25kV class underground distribution, with a load break disconnect variant. The element is silver in a silica sand fill within a fiberglass body.
What voltage ratings are DENCO loadbreak elbow fuses available in?
DENCO loadbreak elbow fuses are supplied at 25kV class. The fuse’s maximum design voltage must be at least your system’s maximum operating voltage, not its nominal, so confirm the system figure when you enquire.
What ampere ratings do DENCO loadbreak elbow fuses cover?
The published range is 20A. Rating is only part of the selection: the melting characteristic, the interrupting rating and the physical envelope all have to match the application as well.
Loadbreak Elbow & Load Break Disconnect FusesSelection guide
What is the interrupting rating of DENCO loadbreak elbow fuses?
50kA. An interrupting rating is a limit rather than a guideline — the fuse must not be applied where the available fault current exceeds it, so check the figure against your system’s fault study.
Loadbreak Elbow & Load Break Disconnect FusesCheck against your fault current
What are DENCO loadbreak elbow fuses used for?
25kV class underground distribution, fused elbow terminations and load break disconnect duty. If your application is close to one of these but not quite the same, describe it when you enquire — the difference usually matters more than the similarity.
Loadbreak Elbow & Load Break Disconnect FusesDescribe your application
What are the application limits for DENCO loadbreak elbow fuses?
Single published rating (20A at 15.5kV) — confirm availability of other ratings with DENCO; elbow and disconnect variants differ; confirm which is required. Limits like these are stated deliberately: a fuse applied outside what it was characterised for can fit, energise and still fail to protect.
Loadbreak Elbow & Load Break Disconnect FusesSelection guide
What standards do DENCO loadbreak elbow fuses follow?
They are tested to CESI-IPH test report Nr. 23152130449.0258. The wording matters and is not decoration: designed to, conforms to, tested to and certified are different strengths of evidence, and this site does not upgrade one into another. If your specification needs a particular level of evidence, ask and DENCO will answer it directly.
Loadbreak Elbow & Load Break Disconnect FusesAsk about standards evidence
How are DENCO loadbreak elbow fuses constructed?
Fiberglass tube body, silver-plated terminals, silver (Ag) element, star tube, silica sand H31, brass bushing. Construction detail matters when a fuse has to fit an existing holder, so confirm the envelope against the installation rather than the description alone.
Loadbreak Elbow & Load Break Disconnect FusesConfirm the fit
Where are DENCO loadbreak elbow fuses covered in the catalog?
Pp.76-77 of DENCO’s January 2025 catalog. Request a copy and the specification tables, dimensions and ratings for this family come with it.
Loadbreak Elbow & Load Break Disconnect FusesRequest the catalog
How do I request a quote for DENCO loadbreak elbow fuses?
Send the part number if you have one, the system voltage, the ampere rating and the standard you must meet, through the quote form. If you are replacing an existing fuse, a photograph of it and its mounting settles the physical details faster than a description. DENCO’s standard lead time is 30 days across all products.
Loadbreak Elbow & Load Break Disconnect FusesRequest a quote
What are DENCO oil-immersed transformer fuses?
DENCO supplies Bay-O-Net fuse holders and fuse links for oil-filled distribution transformers, together with oil-submersible current-limiting backup fuses. The holder, the fault-sensing link and the backup fuse perform distinct protective functions and are selected together.
What are DENCO oil-immersed transformer fuses used for?
Oil-filled distribution transformer protection and pad-mount and subsurface installations. If your application is close to one of these but not quite the same, describe it when you enquire — the difference usually matters more than the similarity.
Oil-Immersed Transformer Fuses: Bay-O-Net & Backup DesignsDescribe your application
What are the application limits for DENCO oil-immersed transformer fuses?
Holder, link and backup fuse are separate components and must be matched; combination selection requires DENCO engineering sign-off. Limits like these are stated deliberately: a fuse applied outside what it was characterised for can fit, energise and still fail to protect.
Oil-Immersed Transformer Fuses: Bay-O-Net & Backup DesignsSelection guide
What standards do DENCO oil-immersed transformer fuses follow?
They are designed to ANSI/IEEE C37.41-2016. The wording matters and is not decoration: designed to, conforms to, tested to and certified are different strengths of evidence, and this site does not upgrade one into another. If your specification needs a particular level of evidence, ask and DENCO will answer it directly.
Oil-Immersed Transformer Fuses: Bay-O-Net & Backup DesignsAsk about standards evidence
What is the melting characteristic of DENCO oil-immersed transformer fuses?
Minimum melting at 60Hz, 25°C ambient, in transformer oil without initial load. Melting time is not clearing time — clearing adds the arcing time needed to actually interrupt the circuit, so a total-clearing figure is always the longer of the two.
Oil-Immersed Transformer Fuses: Bay-O-Net & Backup DesignsTime-current curves and I²t
How many DENCO oil-immersed transformer fuses part numbers are there?
The catalog lists 7 catalog numbers for this family, across pp.78-88. DENCO confirmed in August 2026 that all catalog part numbers are current. Send the number you hold and it will be identified against the range.
Oil-Immersed Transformer Fuses: Bay-O-Net & Backup DesignsRequest the catalog
How do I request a quote for DENCO oil-immersed transformer fuses?
Send the part number if you have one, the system voltage, the ampere rating and the standard you must meet, through the quote form. If you are replacing an existing fuse, a photograph of it and its mounting settles the physical details faster than a description. DENCO’s standard lead time is 30 days across all products.
Oil-Immersed Transformer Fuses: Bay-O-Net & Backup DesignsRequest a quote
BS88, NH & Type HH
DENCO’s British, German, French and IEC-pattern ranges.
What are DENCO BS88 fuses?
DENCO BS88 British Standard fuses are semiconductor-type ultra-rapid fuses with high breaking capacity and low power dissipation. They are used in UK and British-specified equipment and in North American UPS applications.
What voltage ratings are DENCO BS88 fuses available in?
DENCO BS88 fuses are supplied at 250V, 300V, 450V, 550V, 690V, 1000V. The fuse’s maximum design voltage must be at least your system’s maximum operating voltage, not its nominal, so confirm the system figure when you enquire.
What is the highest voltage DENCO BS88 fuses are available in?
1000V is the top of the published range, which runs 250V, 300V, 450V, 550V, 690V, 1000V. If your application sits above that, send the details — this is the catalog range, not the limit of what DENCO can discuss.
What ampere ratings do DENCO BS88 fuses cover?
The published range is 2A to 600A. Rating is only part of the selection: the melting characteristic, the interrupting rating and the physical envelope all have to match the application as well.
What is the interrupting rating of DENCO BS88 fuses?
200kA and 300kA. An interrupting rating is a limit rather than a guideline — the fuse must not be applied where the available fault current exceeds it, so check the figure against your system’s fault study.
What are DENCO BS88 fuses used for?
UK and British-manufactured equipment and north American UPS applications. If your application is close to one of these but not quite the same, describe it when you enquire — the difference usually matters more than the similarity.
What are the application limits for DENCO BS88 fuses?
Semiconductor-type ultra-rapid characteristic — confirm suitability for general-purpose duty. Limits like these are stated deliberately: a fuse applied outside what it was characterised for can fit, energise and still fail to protect.
What standards do DENCO BS88 fuses follow?
They are designed to IEC 269.4, IEC 33, VDE 636-23, DIN 43653 and BS 88-4. The wording matters and is not decoration: designed to, conforms to, tested to and certified are different strengths of evidence, and this site does not upgrade one into another. If your specification needs a particular level of evidence, ask and DENCO will answer it directly.
Where are DENCO BS88 fuses covered in the catalog?
Pp.89-90 of DENCO’s January 2025 catalog. Request a copy and the specification tables, dimensions and ratings for this family come with it.
How do I request a quote for DENCO BS88 fuses?
Send the part number if you have one, the system voltage, the ampere rating and the standard you must meet, through the quote form. If you are replacing an existing fuse, a photograph of it and its mounting settles the physical details faster than a description. DENCO’s standard lead time is 30 days across all products.
What are DENCO NH square body fuses?
DENCO Type NH square body fuses are knife-blade fuses in sizes NH000 to NH5, supplied to German, French and American standards and in press-pack form. Matching Type NH fuse bases are available from 2 to 2000A at 690V.
What voltage ratings are DENCO NH square body fuses available in?
DENCO NH square body fuses are supplied at 500V/660V, 690V/800V, 1000V/1300V, 1000V/1250V. The fuse’s maximum design voltage must be at least your system’s maximum operating voltage, not its nominal, so confirm the system figure when you enquire.
What is the highest voltage DENCO NH square body fuses are available in?
1300V is the top of the published range, which runs 500V/660V, 690V/800V, 1000V/1300V, 1000V/1250V. If your application sits above that, send the details — this is the catalog range, not the limit of what DENCO can discuss.
Type NH Square Body Fuses & BasesAsk about a special requirement
What ampere ratings do DENCO NH square body fuses cover?
The published range is 2A to 2000A. Rating is only part of the selection: the melting characteristic, the interrupting rating and the physical envelope all have to match the application as well.
What is the interrupting rating of DENCO NH square body fuses?
80kA and 120kA. An interrupting rating is a limit rather than a guideline — the fuse must not be applied where the available fault current exceeds it, so check the figure against your system’s fault study.
Type NH Square Body Fuses & BasesCheck against your fault current
What are DENCO NH square body fuses used for?
DC common bus and DC drives, power converters and rectifiers, reduced voltage starters and mining applications (gB). If your application is close to one of these but not quite the same, describe it when you enquire — the difference usually matters more than the similarity.
What are the application limits for DENCO NH square body fuses?
Utilization category must match the duty — aR is semiconductor protection, not general purpose. Limits like these are stated deliberately: a fuse applied outside what it was characterised for can fit, energise and still fail to protect.
What standards do DENCO NH square body fuses follow?
They are designed to DIN 43620, IEC 60269, DIN 43653, VDE 0636 and BS 88. The wording matters and is not decoration: designed to, conforms to, tested to and certified are different strengths of evidence, and this site does not upgrade one into another. If your specification needs a particular level of evidence, ask and DENCO will answer it directly.
Type NH Square Body Fuses & BasesAsk about standards evidence
What sizes are DENCO NH square body fuses available in?
NH000, NH00, NH0, NH1, NH2, NH3, NH4, NH5. The physical envelope has to match the holder as well as the electrical duty, so send the mounting details or a photograph with your enquiry.
What design types are DENCO NH square body fuses available in?
German Standard, French Standard, American Standard, Press-Pack. The physical envelope has to match the holder as well as the electrical duty, so send the mounting details or a photograph with your enquiry.
How are DENCO NH square body fuses mounted?
Type NH, 2 to 2000A, 690V. Mounting style is not interchangeable even where the electrical ratings match, so clip centres or bolt centres need to be confirmed against the existing installation.
What series or type designations do DENCO NH square body fuses carry?
aR, gL/gG, aM, gTR, gB, gR. These are the designations to quote when identifying an existing fuse, and several of them are the names buyers search for rather than the DENCO catalog number itself.
Where are DENCO NH square body fuses covered in the catalog?
Pp.91-95 of DENCO’s January 2025 catalog. Request a copy and the specification tables, dimensions and ratings for this family come with it.
How do I request a quote for DENCO NH square body fuses?
Send the part number if you have one, the system voltage, the ampere rating and the standard you must meet, through the quote form. If you are replacing an existing fuse, a photograph of it and its mounting settles the physical details faster than a description. DENCO’s standard lead time is 30 days across all products.
What are DENCO Type HH fuse-links?
DENCO Type HH high-voltage HRC fuse-links are current-limiting German-style fuses for medium and high voltage distribution networks, transformers and capacitors. They are available for indoor, outdoor and oil-submerged applications.
What voltage ratings are DENCO Type HH fuse-links available in?
DENCO Type HH fuse-links are supplied at 7.2kV, 8.3kV, 17.5kV, 24kV, 36kV. The fuse’s maximum design voltage must be at least your system’s maximum operating voltage, not its nominal, so confirm the system figure when you enquire.
What is the highest voltage DENCO Type HH fuse-links are available in?
36kV is the top of the published range, which runs 7.2kV, 8.3kV, 17.5kV, 24kV, 36kV. If your application sits above that, send the details — this is the catalog range, not the limit of what DENCO can discuss.
Type HH High Voltage HRC Fuse-LinksAsk about a special requirement
What ampere ratings do DENCO Type HH fuse-links cover?
The published range is 2A to 400A. Rating is only part of the selection: the melting characteristic, the interrupting rating and the physical envelope all have to match the application as well.
What are DENCO Type HH fuse-links used for?
Medium to high voltage distribution networks, transformer and capacitor protection and primary, back-up and full-range duty. If your application is close to one of these but not quite the same, describe it when you enquire — the difference usually matters more than the similarity.
Type HH High Voltage HRC Fuse-LinksDescribe your application
What are the application limits for DENCO Type HH fuse-links?
Indoor, outdoor and oil-submerged variants differ — confirm the application. Limits like these are stated deliberately: a fuse applied outside what it was characterised for can fit, energise and still fail to protect.
What standards do DENCO Type HH fuse-links follow?
They are designed to DIN 43625, IEC 282-1, VDE 0670, EN 60644, IEC 60282-1, IEC 60644 and IEC 60787. The wording matters and is not decoration: designed to, conforms to, tested to and certified are different strengths of evidence, and this site does not upgrade one into another. If your specification needs a particular level of evidence, ask and DENCO will answer it directly.
Type HH High Voltage HRC Fuse-LinksAsk about standards evidence
What lengths are DENCO Type HH fuse-links available in?
192mm, 292mm, 442mm, 537mm. The physical envelope has to match the holder as well as the electrical duty, so send the mounting details or a photograph with your enquiry.
Where are DENCO Type HH fuse-links covered in the catalog?
Pp.96-97 of DENCO’s January 2025 catalog. Request a copy and the specification tables, dimensions and ratings for this family come with it.
How do I request a quote for DENCO Type HH fuse-links?
Send the part number if you have one, the system voltage, the ampere rating and the standard you must meet, through the quote form. If you are replacing an existing fuse, a photograph of it and its mounting settles the physical details faster than a description. DENCO’s standard lead time is 30 days across all products.
Semiconductor protection
Ultra-rapid fuses for thyristors, rectifiers, drives and traction.
What are DENCO ultra-rapid semiconductor fuses?
DENCO ultra-rapid semiconductor fuses protect thyristors, diodes, rectifiers and other solid-state devices. They are current-limiting with very low I²t let-through, supplied in Form 101 cylindrical, NH square body and ferrule cartridge formats.
What voltage ratings are DENCO ultra-rapid semiconductor fuses available in?
DENCO ultra-rapid semiconductor fuses are supplied at 130V, 250V, 500V, 600V, 700V, 1000V, 1200V, 1500V. The fuse’s maximum design voltage must be at least your system’s maximum operating voltage, not its nominal, so confirm the system figure when you enquire.
What is the highest voltage DENCO ultra-rapid semiconductor fuses are available in?
1500V is the top of the published range, which runs 130V, 250V, 500V, 600V, 700V, 1000V, 1200V, 1500V. If your application sits above that, send the details — this is the catalog range, not the limit of what DENCO can discuss.
Ultra-Rapid Semiconductor FusesAsk about a special requirement
What ampere ratings do DENCO ultra-rapid semiconductor fuses cover?
The published range is 1A to 2000A. Rating is only part of the selection: the melting characteristic, the interrupting rating and the physical envelope all have to match the application as well.
What is the interrupting rating of DENCO ultra-rapid semiconductor fuses?
200kA AC, 100kA DC. An interrupting rating is a limit rather than a guideline — the fuse must not be applied where the available fault current exceeds it, so check the figure against your system’s fault study.
Ultra-Rapid Semiconductor FusesCheck against your fault current
What are DENCO ultra-rapid semiconductor fuses used for?
Thyristors, triacs and diodes, electrochemical rectifiers, DC drives, UPS and inverters and heavy traction equipment. If your application is close to one of these but not quite the same, describe it when you enquire — the difference usually matters more than the similarity.
What are the application limits for DENCO ultra-rapid semiconductor fuses?
Ultra-rapid characteristic — not a substitute for general-purpose overload protection. Limits like these are stated deliberately: a fuse applied outside what it was characterised for can fit, energise and still fail to protect.
What standards do DENCO ultra-rapid semiconductor fuses follow?
They are in accordance with IEC 269.1, VDE 636-23 and UL / CSA. The wording matters and is not decoration: designed to, conforms to, tested to and certified are different strengths of evidence, and this site does not upgrade one into another. If your specification needs a particular level of evidence, ask and DENCO will answer it directly.
What form 101 ampere range are DENCO ultra-rapid semiconductor fuses available in?
1A to 2000A. The physical envelope has to match the holder as well as the electrical duty, so send the mounting details or a photograph with your enquiry.
What ferrule sizes are DENCO ultra-rapid semiconductor fuses available in?
10x38, 14x51, 22x58, 27x60, 20x76, 20x127 (mm). The physical envelope has to match the holder as well as the electrical duty, so send the mounting details or a photograph with your enquiry.
How many DENCO ultra-rapid semiconductor fuses part numbers are there?
The catalog lists 98 catalog numbers for this family, across pp.98-132. DENCO confirmed in August 2026 that all catalog part numbers are current. Send the number you hold and it will be identified against the range.
How do I request a quote for DENCO ultra-rapid semiconductor fuses?
Send the part number if you have one, the system voltage, the ampere rating and the standard you must meet, through the quote form. If you are replacing an existing fuse, a photograph of it and its mounting settles the physical details faster than a description. DENCO’s standard lead time is 30 days across all products.
Solar, EV & special purpose
gPV photovoltaic, electric vehicle DC and network protector fuses.
What are DENCO gPV photovoltaic fuses?
DENCO gPV photovoltaic fuses protect solar DC strings and combiner boxes, with matching fuse bases. They are full-range DC fuses rated for photovoltaic duty from 600 to 1500VDC.
What voltage ratings are DENCO gPV photovoltaic fuses available in?
DENCO gPV photovoltaic fuses are supplied at 600VDC to 1500VDC. These are DC ratings and are not interchangeable with an AC rating of the same number — a fuse must be rated for the current type it will interrupt.
What are DENCO gPV photovoltaic fuses used for?
Solar PV string and array protection, combiner boxes and alternative energy DC systems. If your application is close to one of these but not quite the same, describe it when you enquire — the difference usually matters more than the similarity.
What are the application limits for DENCO gPV photovoltaic fuses?
PV duty only — gPV is not interchangeable with gG or aR; string sizing requires the system design; see the solar RFQ guide. Limits like these are stated deliberately: a fuse applied outside what it was characterised for can fit, energise and still fail to protect.
What standards do DENCO gPV photovoltaic fuses follow?
They are conform to IEC 60269-1, IEC 60269-6 and DIN VDE 0636-2. The wording matters and is not decoration: designed to, conforms to, tested to and certified are different strengths of evidence, and this site does not upgrade one into another. If your specification needs a particular level of evidence, ask and DENCO will answer it directly.
What series or type designations do DENCO gPV photovoltaic fuses carry?
gPV. These are the designations to quote when identifying an existing fuse, and several of them are the names buyers search for rather than the DENCO catalog number itself.
Where are DENCO gPV photovoltaic fuses covered in the catalog?
Pp.138-140 of DENCO’s January 2025 catalog. Request a copy and the specification tables, dimensions and ratings for this family come with it.
How do I request a quote for DENCO gPV photovoltaic fuses?
Send the part number if you have one, the system voltage, the ampere rating and the standard you must meet, through the quote form. If you are replacing an existing fuse, a photograph of it and its mounting settles the physical details faster than a description. DENCO’s standard lead time is 30 days across all products.
What are DENCO electric vehicle DC fuses?
DENCO electric vehicle DC fuses are compact current-limiting fuses for high-voltage DC vehicle and charging applications, supplied from 500 to 1500VDC.
What voltage ratings are DENCO electric vehicle DC fuses available in?
DENCO electric vehicle DC fuses are supplied at 500V, 700V, 1000V, 1500V DC. These are DC ratings and are not interchangeable with an AC rating of the same number — a fuse must be rated for the current type it will interrupt.
What is the highest voltage DENCO electric vehicle DC fuses are available in?
1500V is the top of the published range, which runs 500V, 700V, 1000V, 1500V DC. If your application sits above that, send the details — this is the catalog range, not the limit of what DENCO can discuss.
What ampere ratings do DENCO electric vehicle DC fuses cover?
The published range is 50A to 400A. Rating is only part of the selection: the melting characteristic, the interrupting rating and the physical envelope all have to match the application as well.
What is the interrupting rating of DENCO electric vehicle DC fuses?
20kA I.R.. An interrupting rating is a limit rather than a guideline — the fuse must not be applied where the available fault current exceeds it, so check the figure against your system’s fault study.
What are DENCO electric vehicle DC fuses used for?
Electric vehicle DC power circuits. If your application is close to one of these but not quite the same, describe it when you enquire — the difference usually matters more than the similarity.
What are the application limits for DENCO electric vehicle DC fuses?
No automotive certification, OEM approval or safety-critical platform use is claimed. Limits like these are stated deliberately: a fuse applied outside what it was characterised for can fit, energise and still fail to protect.
Where are DENCO electric vehicle DC fuses covered in the catalog?
P.137 + line card p.3 of DENCO’s January 2025 catalog. Request a copy and the specification tables, dimensions and ratings for this family come with it.
How do I request a quote for DENCO electric vehicle DC fuses?
Send the part number if you have one, the system voltage, the ampere rating and the standard you must meet, through the quote form. If you are replacing an existing fuse, a photograph of it and its mounting settles the physical details faster than a description. DENCO’s standard lead time is 30 days across all products.
What are DENCO network protector fuses?
DENCO network protector fuses are high breaking capacity fuses for the protection of circuit breakers in underground distribution networks.
What voltage ratings are DENCO network protector fuses available in?
DENCO network protector fuses are supplied at 600VAC maximum. The fuse’s maximum design voltage must be at least your system’s maximum operating voltage, not its nominal, so confirm the system figure when you enquire.
What ampere ratings do DENCO network protector fuses cover?
The published range is 800A to 3000A. Rating is only part of the selection: the melting characteristic, the interrupting rating and the physical envelope all have to match the application as well.
What is the interrupting rating of DENCO network protector fuses?
200kA. An interrupting rating is a limit rather than a guideline — the fuse must not be applied where the available fault current exceeds it, so check the figure against your system’s fault study.
What are DENCO network protector fuses used for?
Circuit breaker protection in underground distribution networks. If your application is close to one of these but not quite the same, describe it when you enquire — the difference usually matters more than the similarity.
What standards do DENCO network protector fuses follow?
They are tested to CESI-IPH report 03160-15-0534-1. The wording matters and is not decoration: designed to, conforms to, tested to and certified are different strengths of evidence, and this site does not upgrade one into another. If your specification needs a particular level of evidence, ask and DENCO will answer it directly.
Where are DENCO network protector fuses covered in the catalog?
Pp.135-136 of DENCO’s January 2025 catalog. Request a copy and the specification tables, dimensions and ratings for this family come with it.
How do I request a quote for DENCO network protector fuses?
Send the part number if you have one, the system voltage, the ampere rating and the standard you must meet, through the quote form. If you are replacing an existing fuse, a photograph of it and its mounting settles the physical details faster than a description. DENCO’s standard lead time is 30 days across all products.
Not answered here?
Send the part number, the system voltage, the ampere rating and the standard you have to meet. If you are replacing an existing fuse, a photograph of it and its mounting usually settles the physical details faster than a description does.