Best Custom Fuse Manufacturers (2026)
DENCO Fuses publishes this list and ranks itself first. Every other company here states on its own website that it offers custom, customer-specific or modified fuses; we checked each site in September 2026. The order after DENCO is not a quality ranking.
Fuse makers that state they do custom or customer-specific work include DENCO Fuses (OEM and specialty custom design), Eaton's Bussmann series Custom Order Engineering team, SIBA, Lawson Fuses, SCHURTER, Bel Fuse and ETI. They cover very different voltage classes, so start with the kind of fuse you need, then ask each maker what it can change: ratings, time-current curve, terminals, dimensions or indication.
How this list was put together
A company made this list only if its own website says it offers custom, customer-specific or modified fuses. General statements about customer service, or custom work on products other than fuses, did not count. The page we relied on for each company is listed in the sources and research notes.
Custom means different things across the industry. Some makers design new fuse-links to a customer's specification; others modify a standard fuse's terminals, dimensions or indication. We describe each one in the terms its own site uses and do not rank those capabilities against each other.
DENCO is first because this is DENCO's site. The reasons it may suit a custom buyer are practical: DENCO serves OEM and specialty custom design customers, works across many medium voltage and DC fuse families, quotes a 30-day lead time and gives direct access to its engineering team.
1. DENCO Fuses, Miami, Florida
Best for: OEM and specialty buyers who need medium voltage or DC fuses and a direct line to engineering
DENCO Fuses, Inc. is a Miami, Florida company, incorporated in Florida in 1988 as DenMar Transit Engineering (later DenMar Fuses), with over 100 years of combined experience solely in manufacturing electrical fuses. OEM and specialty custom design is one of the customer segments DENCO serves, alongside utilities, electrical contractors and transit.
The standard range that custom and OEM inquiries start from is broad: E-rated, R-rated, PT, C-rated capacitor, DHS/DHHS dropout, loadbreak elbow, oil-immersed transformer, Type HH, semiconductor, gPV (600 to 1500 VDC), EV DC (500 to 1500 VDC) and network protector fuses. Fuses are manufactured in an ISO 9001:2015 certified facility and tested in-house at DENCO's factory lab, with third-party testing at IPH Berlin (Germany) available on client request.
Lead time is 30 days on all products, where the industry norm is commonly longer. To discuss an OEM or specialty requirement, call 1-800-305-FUSE (3873) or (305) 273-6226, or send an RFQ.
- OEM and specialty custom design customer segment
- Medium voltage and DC fuse families from one supplier
- Third-party testing at IPH Berlin on client request
2. Eaton Bussmann series Custom Order Engineering
Best for: Modifying a standard Bussmann series fuse, including mounting hardware for medium voltage fuses
Eaton says its Custom Order Engineering team can modify an existing Bussmann series product or develop an all-new product when one of its more than 70,000 standard products will not work. Examples on Eaton's page include wire terminations for harnesses, lug and screw hardware options, remote indication added to fuses, and mounting brackets for medium voltage fuses sized for the customer's gear.
3. SIBA, Lunen, Germany
Best for: Custom fuse-link development across high-voltage, semiconductor and low-voltage lines
SIBA was founded in 1946 in Lunen, Germany, and says it has developed and manufactured only fuse-links since then. Its site advertises custom engineering to customer specifications and describes developing custom fuse-link solutions with customers through collaborative projects. SIBA's catalog spans HH high-voltage, UltraRapid semiconductor, low-voltage high-performance, miniature and special fuses, with more than 10,000 fuse-link types and accessories.
4. Lawson Fuses (Lucy Group), United Kingdom
Best for: Low voltage HRC fuse-links built to specification, including contract design and manufacturing
Lawson Fuses has designed and manufactured low voltage HRC fuse-links and fuse-holders since 1938 and has been part of Lucy Group since 2018. Its custom fuse solutions page describes building to specification through a Contract Design and Manufacturing (CDM) service that covers concept design, prototyping, testing, certification and production, with manufacturing in Newcastle upon Tyne (UK) and Vadodara (India).
5. SCHURTER, Switzerland
Best for: Customer-specific fuses for electronics, including aerospace and space programs
SCHURTER, a Swiss technology company, states that it offers customer-specific fuses with different characteristics. Its customer-specific components page cites the MGA-S and HCSF fuses developed in cooperation with the European Space Agency (ESA), and lists markets including aerospace, industrial equipment, medical devices, automotive and energy.
6. Bel Fuse (Bel Circuit Protection)
Best for: Customizable fuses and resettable PTCs for automotive, industrial, consumer electronics and telecom designs
Bel's circuit protection line includes fuses, fuse holders and resettable PTCs for automotive, industrial, consumer electronics and telecommunications systems. Bel's page says its circuit protection products offer customization options and that it can develop tailored solutions for a design.
7. ETI Elektroelement, Izlake, Slovenia
Best for: IEC high-voltage fuse-links in non-standard dimensions
ETI's VV high-voltage current-limiting fuse-links, built to IEC 60282-1 for distribution transformers, power capacitors and MV motors, can be supplied in non-standard dimensions on request, according to ETI's data sheet, which charts the standard and non-standard body sizes offered at each voltage.
What custom can mean for a fuse
Before you contact anyone, decide which of these you actually need. A modified standard fuse is usually faster and cheaper to qualify than a new design, and several makers above describe both options.
- Mechanical changes: special terminals, lugs, mounting brackets or body dimensions to fit existing gear.
- Indication: adding a blown-fuse indicator, striker or microswitch for remote signaling.
- Electrical changes: a current rating or time-current characteristic that differs from the catalog, which means new type testing.
- A new design for a new application, such as an emerging DC system, where no standard fuse exists yet.
- Private-label or co-branded supply of an existing fuse.
What to send with a custom fuse inquiry
A custom fuse is only as good as the specification behind it. The equipment designer, not the fuse maker, owns the protection requirements, and the fuse maker needs them in writing.
- System voltage (ac or dc), continuous current, available fault current and required interrupting rating.
- The time-current or I2t limits the fuse must meet, from your coordination study or the protected device's data.
- Mounting, envelope dimensions, terminal style and ambient conditions (temperature, enclosure, oil or gas).
- Which standard the fuse must be tested to, and whether you need third-party test reports.
- Quantities, the part number of any fuse it replaces, and your schedule.
Frequently asked questions
Does DENCO make custom fuses?
DENCO serves OEM and specialty custom design customers as one of its customer segments. Call 1-800-305-FUSE (3873) or send an RFQ with your requirements and DENCO engineering will respond.
How long does a custom fuse take?
It depends on how much changes. A mechanical change to a standard fuse can be quick; a new electrical design needs development and type testing. DENCO's lead time on its products is 30 days; ask any supplier for a schedule on your specific requirement.
Does a custom fuse need to be tested again?
Usually, if the change affects ratings, the time-current characteristic or interrupting performance. The relevant standard (for example IEC 60282-1 or the IEEE C37 fuse standards for high voltage fuses) sets the tests. Ask which tests the maker will run and whether reports come from an independent lab.
Can I get a replacement for an obsolete fuse without a custom design?
Often yes. Check cross-reference options first: DENCO publishes six cross-references and will confirm others when you send the part number.
Limits of this article
- A custom fuse must be specified from the equipment manufacturer's data and a protection coordination study by a qualified engineer; the fuse maker cannot set your protection requirements.
- Each company's custom capability is described as stated on its website in September 2026. What a maker will take on for a given voltage class, volume or schedule can only be confirmed by asking it.
- Changes to rating or characteristic generally require type testing to the applicable standard before the fuse is used in service.
- Installing or replacing fuses near energized equipment requires qualified personnel, NFPA 70E PPE and lockout/tagout.
Related
- Request a quote
- DENCO product families
- Fuse cross-reference
- Time-current curves and I2t guide
- Best Medium Voltage Fuse Manufacturers