Best Semiconductor Fuse Manufacturers (2026)

How this list was put together

We started from the formats DENCO’s own semiconductor range covers: Form 101 cylindrical fuses, NH square-body fuses and ferrule cartridge fuses. We then looked for manufacturers whose own websites publish a dedicated semiconductor or high-speed fuse range, and loaded each site in September 2026. Where a site blocked automated access, we recorded that and used only text indexed from that manufacturer's own domain.

Each entry says what the manufacturer publishes about its range and who it tends to suit. We did not test competitor products, and we make no performance comparison between them. DENCO is first because this is DENCO's site; its entry gives buyer-fit reasons rather than a technical claim that it outperforms anyone else.

1. DENCO Fuses, Miami, Florida

Best for: Buyers who want Form 101, square-body and ferrule semiconductor fuses from one supplier on a 30-day lead time

DENCO Fuses, Inc. was incorporated in Florida in 1988 as DenMar Transit Engineering (later DenMar Fuses). Its team has over 100 years of combined experience, solely in manufacturing electrical fuses. The ultra-rapid semiconductor family covers Form 101 cylindrical fuses, NH square-body fuses and ferrule fuses, so a plant that runs drives, rectifiers and UPS equipment from several original makers can often consolidate those formats with one supplier.

DENCO quotes a 30-day lead time on all products; lead times across the industry are commonly longer. Fuses are manufactured in an ISO 9001:2015 certified facility, tested in-house at DENCO's factory lab, and can be sent for third-party testing at IPH Berlin (Germany) on client request.

If you are replacing an existing semiconductor fuse from another brand, send the part number and DENCO engineering will confirm whether there is a suitable DENCO part. DENCO does not publish equivalences to other brands' semiconductor fuses, so every replacement is checked individually.

• Formats: Form 101 cylindrical, NH square body, ferrule
• 30-day lead time on all products
• In-house factory lab testing; IPH Berlin third-party testing on request
• Serves OEM and specialty custom design customers, utilities, contractors and transit
• Direct line to engineering: 1-800-305-FUSE (3873)

See the DENCO range

2. Eaton, Bussmann series high speed fuses

Best for: Engineers designing drives and power converters who want a very broad high-speed catalog with both UL and IEC product lines

Eaton sells its high-speed fuses under the Bussmann series name. Its product pages describe high-speed square-body fuses for AC and DC drives, power converters, rectifiers and variable speed drives, alongside high-speed ferrule fuses that fit Bussmann modular fuse holders and are offered for both North American and IEC markets.

Eaton also publishes application guides for high-speed fuses and separate lines aimed at electric vehicle and charging-station power electronics.

• Square-body and ferrule high-speed formats
• Published application guide for high-speed fuse selection
• Separate EV and charging-station high-speed lines

Eaton (Bussmann series) website

3. Mersen, high-speed and semiconductor fuses

Best for: Panel builders who want a UL Class J footprint with semiconductor-level I²t, or aR fuses for high-power DC conversion

Mersen's high-speed range is split into several families on its website, including square-body and IEC cylindrical-body styles. The HSJ (High Speed Class J) is UL listed to UL 248-8 and, in Mersen's words, combines the low I²t of a semiconductor fuse with the branch-circuit performance of a Class J fuse, for drives, soft-starters, solid-state relays and phase controllers.

For DC power conversion, Mersen's D100QS series is a North American round-body aR fuse rated 1000 VDC, described as designed to reduce I²t, peak let-through current and arc voltage in applications such as battery charging systems.

• HSJ: UL 248-8 Class J with low I²t
• D100QS: aR, 1000 VDC round body for DC conversion
• Published HSJ selection tables for several drive brands

Mersen website

4. Littelfuse, POWR-SPEED high-speed fuses

Best for: OEMs already buying Littelfuse circuit protection who want round-body and square-body high-speed fuses in one catalog

Littelfuse groups its range under high-speed semiconductor fuses, with POWR-SPEED round-body fuses and PSR series square-body fuses. The company describes the PSR range as designed to protect diodes, triacs, IGBTs, SCRs, MOSFETs and other solid-state devices used in power conversion and power conditioning equipment.

Littelfuse also publishes a 1500 VDC high-speed square-body fuse (ESR series) aimed at battery modules.

• POWR-SPEED round-body series (for example L15S, L25S, KLC)
• PSR square-body series
• ESR 1500 VDC square body for battery applications

Littelfuse website

5. SIBA, UltraRapid semiconductor fuses

Best for: European-standard equipment and battery or photovoltaic power electronics needing many body styles

SIBA says it has developed and manufactured only fuse-links since it was founded in 1946 and describes itself as a family-run business. Its UltraRapid range is offered as URZ (cylindrical), URB (screw terminals), URM (blade contacts), URS (square design) and URE (British standard) designs, with matching holders, bases and indicators.

SIBA lists photovoltaic systems, battery energy storage, frequency converters, data centers and railway applications among the uses for UltraRapid fuses, and states that its products comply with IEC, UL, VDE and CE requirements.

• Five UltraRapid construction families (URZ, URB, URM, URS, URE)
• Fuse-link specialist since 1946
• Holders, bases and indicator systems in the same range

SIBA website

6. Siemens, SENTRON SITOR semiconductor fuses

Best for: Sites standardized on Siemens drives and switchgear that want the fuse from the same supplier

Siemens sells semiconductor fuses as SENTRON SITOR. Siemens describes them as providing ultra-fast short-circuit protection for power semiconductors in converters, UPS systems and soft starters. For North America, Siemens lists SITOR among its UL-approved fuse portfolio alongside Class CC and Class J fuses.

• SITOR semiconductor fuses within the SENTRON fuse systems range
• Applications named by Siemens: converters, UPS, soft starters

Siemens (SENTRON SITOR) website

7. Hinode Electric Co., Ltd., Tokyo, Japan

Best for: Compact fast-acting fuses for servo drives, inverters and UPS, especially in Japanese-built equipment

Hinode Electric says it is Japan's only manufacturer specializing in fast-acting fuses for semiconductor protection. The company has made fuses since its founding in 1955 and began making fast-acting semiconductor fuses in 1974. Its head office and factory are in Adachi-ku, Tokyo.

The published catalog is organized into compact fast-acting fuses, cylindrical fast-acting fuses and application-specific fuses. Hinode's site names servo motor drivers, inverters, UPS, machine tools, solar power and storage batteries among target uses, and it publishes a warning about imitation Hinode products, which is worth reading if you buy through secondary channels.

• Semiconductor-protection fuse specialist since 1974
• Compact, cylindrical and application-specific series
• Head office and factory in Tokyo

Hinode Electric website

What makes a fuse a semiconductor fuse

A semiconductor fuse (also called a high-speed or ultra-rapid fuse) is a current-limiting fuse designed to clear a short circuit fast enough, and with low enough let-through energy (I²t), that a diode, thyristor or IGBT survives. Ordinary general-purpose fuses are too slow for this job.

Internationally, IEC 60269-4 sets the supplementary requirements for fuse-links that protect semiconductor devices, in equipment for circuits up to 1000 V AC or 1500 V DC (the 2024 edition notes that some fuse-links can be used at higher rated voltages). In North America, UL 248-13 covers semiconductor fuses rated 2000 V AC or less, with DC ratings optional. Many semiconductor fuses are short-circuit-only (the IEC "aR" category), which means an overload has to be handled by another device.

How to choose between these manufacturers

Start from the equipment, not the brand: a replacement has to match the original fuse's I²t and arc-voltage behavior, not only voltage, amperage and body size.

• Format first: Form 101 round body, square body (NH-style, flush-end or bolted), or ferrule. Mounting and body size are usually fixed by the equipment.
• Standard second: check whether the equipment was built around IEC 60269-4 or UL 248-13 fuses, and whether the installation needs a specific listing.
• Electrical match: voltage (AC and DC separately), current rating, interrupting rating, total clearing I²t and peak arc voltage all need confirming against the device data.
• Indicators and microswitches: many converters monitor fuse status, so the replacement must support the same indicator or switch.
• Lead time and support: for maintenance stock, a shorter lead time and a direct engineering contact often matter as much as catalog breadth.

Replacing an obsolete or hard-to-get semiconductor fuse

Semiconductor fuses are one of the most common reasons plants call around for a cross-reference, because the equipment outlives the original part number. DENCO's cross-reference page accepts any manufacturer's part number: send it with a photo of the fuse and nameplate data for the equipment, and DENCO engineering will confirm whether a DENCO part fits.

Frequently asked questions