Best Fuses for EV Charging Infrastructure

About this list

This list follows the power path of a DC fast charging site: from the utility's medium-voltage supply and service transformer, through the charger's AC input and power conversion stages, to the DC output and any battery buffer. It names the fuse type normally used at each stage and the standard that defines it. It is a map of fuse types, not a ranking of suppliers.

1. 1. High-speed semiconductor fuses in the power modules

In short: Protecting the rectifier and DC-DC converter stages inside a DC fast charger

A DC fast charger converts AC from the grid into a controlled DC output using power semiconductors: rectifier diodes or active front ends, IGBT or silicon carbide switches, and DC-DC stages. A short circuit in that path has to be cleared before the semiconductors fail, which calls for a high-speed (semiconductor) fuse with low let-through energy (I²t).

IEC 60269-4 sets the supplementary requirements for fuse-links protecting semiconductor devices in circuits up to 1000 V AC or 1500 V DC, and UL 248-13 covers semiconductor fuses in North America. Fuse makers now publish DC-rated high-speed ranges aimed specifically at battery charging systems and high-power DC conversion.

• Categories: aR (short-circuit only) or gR (full-range)
• Standards: IEC 60269-4; UL 248-13
• Replace like for like: match I²t, arc voltage and DC rating

See the DENCO range

2. 2. DC fuses on the charger's DC bus and output

In short: DC circuits between the power modules and the charging cable, at 500 to 1500 VDC

IEC 61851-23 covers DC EV supply equipment rated up to 1000 V AC or 1500 V DC on the supply side and up to 1500 V DC on the vehicle side. Across that range, the DC circuits inside the charger need fuses whose DC voltage rating covers the maximum output voltage, with an interrupting rating that suits the available fault current from both the converter and the vehicle battery.

DENCO's electric vehicle DC fuses are compact current-limiting fuses for high-voltage DC vehicle and charging applications, supplied from 500 to 1500 VDC. DENCO does not claim automotive certification or OEM approval for this family, so treat it as a charging-infrastructure product and confirm its fit with DENCO engineering.

• DC voltage rating must cover the charger's maximum output voltage
• Check DC interrupting rating, not only the AC rating
• DENCO EV DC fuse family: 500 to 1500 VDC

See the DENCO range

3. 3. Know the difference between charger fuses and on-vehicle EV fuses

In short: Avoiding the wrong standard when a specification just says "EV fuse"

"EV fuse" can mean two different things. UL 248-20 is an outline of investigation for fuses used as overcurrent protection in an electric vehicle power circuit where NEC branch-circuit protection is not required: that is, fuses inside the vehicle. Fuses in a fixed charger installed under the NEC are a different case, and the charger manufacturer specifies which standard applies to each position.

When a specification or RFQ just says "EV fuse", ask whether the part goes into the vehicle or into the charging equipment before you compare parts.

• UL 248-20: fuses in the vehicle's power circuit
• Charger fuses: follow the charger maker's specification
• Clarify vehicle versus infrastructure before quoting

Charger fuses versus vehicle EV fuses website

4. 4. AC input and branch-circuit fuses

In short: The charger's AC supply connection and feeder protection

The AC feed to each charger needs branch-circuit protection under the NEC, often from UL 248 low-voltage fuses or circuit breakers. Where the AC input also feeds power semiconductors directly, some designers use fuses that combine a branch-circuit class with low I²t: for example, fuses sold as high-speed Class J combine UL Class J branch-circuit performance with semiconductor-level let-through.

The charger manufacturer's installation manual specifies the maximum fuse size and class for the AC input. Follow it exactly.

• Branch-circuit fuses: UL 248 classes
• High-speed Class J designs combine branch-circuit and semiconductor protection
• Maximum size and class come from the charger's installation manual

AC input fuses website

5. 5. Battery fuses for on-site storage buffers

In short: Charging sites that use battery storage to reduce peak demand or supplement a limited grid connection

Some charging sites add stationary battery storage to buffer demand. Battery fault currents can be very high and rise quickly, and fuses for this duty have their own categories, gBat (full-range) and aBat (partial-range).

IEC 60269-7 sets the supplementary requirements for fuse-links protecting batteries and battery systems up to 1500 V DC. In North America, UL 248-21 (first edition October 2025) covers fuses protecting batteries and battery systems rated 2000 V DC or less. A general-purpose or PV fuse is not a substitute.

• Categories: gBat and aBat
• Standards: IEC 60269-7; UL 248-21
• Rack, bank and module positions

Battery fuses for storage buffers website

6. 6. Medium-voltage fuses for the service transformer

In short: Charging hubs fed from the utility's medium-voltage distribution system

A site with several DC fast chargers usually needs its own utility transformer stepping medium-voltage distribution down to 480 VAC, and integrated charging power modules are now built with medium-voltage switchgear and a transformer in one package. The fuses on that transformer's primary depend on the equipment type.

Oil-filled pad-mounted transformers are usually self-protected by a bayonet fuse in series with a backup current-limiting fuse. Transformers fed from medium-voltage switchgear or fused switches commonly use E-rated current-limiting fuses; ANSI/IEEE C37.46 defines the E rating (100 E or less: melts in 300 seconds at 200 to 240% of rating; above 100 E: melts in 600 seconds at 220% to 264%). Underground dead-front systems may use loadbreak elbow fuses at the cable termination.

• Pad-mount: Bay-O-Net plus backup current-limiting fuse
• Switchgear-fed: E-rated current-limiting fuses (ANSI/IEEE C37.46)
• Underground dead-front: 25 kV class loadbreak elbow fuses

See the DENCO range

7. 7. gPV fuses where the site has its own solar array

In short: Charging sites with rooftop or canopy PV feeding the site

If the charging site has its own PV array, the DC side of that array needs gPV fuses, the full-range photovoltaic category defined in IEC 60269-6 and covered in North America by UL 248-19. These are different fuses from the charger's DC fuses even when the voltages look similar: gPV fuses are built for the low fault currents of PV strings, not the output of a power converter. DENCO's gPV fuses and bases cover 600 to 1500 VDC.

• Category: gPV
• Standards: IEC 60269-6; UL 248-19
• Not interchangeable with charger DC or semiconductor fuses

See the DENCO range

Why DC ratings matter more than amp ratings

A fuse interrupting DC has no natural current zero to help extinguish the arc, so a fuse's AC voltage rating says little about what it can do in a DC circuit. For every fuse on the DC side of a charger, confirm the DC voltage rating, the DC interrupting rating and, for semiconductor protection, the total clearing I²t and peak arc voltage. The circuit's time constant (L/R) also affects DC interruption, so check the fuse maker's data for the time constant used in its DC ratings.

What to send when you request a quote

For DENCO or any other supplier, a quote for EV charging fuses is fastest when it includes:

• Voltage, and whether each position is AC or DC
• Continuous current and the required interrupting rating
• Physical dimensions and mounting, or the part number being replaced
• Whether an indicator or microswitch is needed
• The standard or approval the installation must meet
• A photo or drawing of the existing part, if there is one

Frequently asked questions