The HSJ400 delivers exceptional high-speed circuit protection with a 600VAC/500VDC rating and a robust 400A current capacity, minimising downtime for critical industrial applications.
£563.62
The Mersen HSJ400 is a high performance Class J high speed semiconductor fuse designed to provide branch circuit protection alongside low let-through energy for sensitive power electronic components. As part of the established Mersen Amp-Trap HSJ Series, it combines the protective characteristics of a semiconductor fuse with the branch circuit performance of a UL Listed Class J fuse.
The HSJ400 is engineered to interrupt damaging fault currents rapidly, helping protect diodes, SCRs, GTOs, solid state relays and other semiconductor devices. Its high speed operating characteristic limits the thermal and electrical energy passed to protected equipment, reducing the risk of component damage, costly repairs and unplanned industrial downtime.
With a rated current of 400 A, an AC voltage rating of 600 V and a DC voltage rating of 500 V, the Mersen HSJ400 is suitable for variable frequency drives, soft starters, power conversion equipment and industrial control systems. Its blade terminals and clip-mounted format provide secure installation in compatible Class J fuse holders and approved electrical equipment.
High speed fuses such as the Mersen HSJ400 are designed to interrupt short-circuit currents before excessive fault energy can damage sensitive semiconductor components. By limiting peak current and let-through energy, the fuse helps protect electronic switching devices that can be more vulnerable to overcurrent conditions than conventional electrical equipment.
The HSJ400 combines Class J branch circuit performance with high speed semiconductor protection, helping simplify industrial electrical system design. It is particularly suitable for high-current applications involving motor drives, power conversion assemblies and electronic control equipment.
| Current | 400 A |
|---|---|
| Voltage | 600 V |
| Item number | HSJ400 |
| Description | Fuse HSJ - Class J - High-Speed 600VAC 500VDC 400A Blade Amp-Trap® |
| EAN/UPC Code | 782001329709 |
| Rated voltage AC UL | 600 V |
| Rated voltage DC UL | 500 V |
| Frequency (Hz) | 50/60 Hz |
| Ampere Rating | 400 A |
| AC or DC | AC/DC |
| Fuse Class | Class J |
| Speed/Characteristic | High Speed |
| Mounting | Clip |
| AC Max I.R./Breaking Capacity | I1: 200 kA |
| Connection/Terminal Material | Brass |
| Connection/Terminal Type | Blade |
| Product Diameter | 54 mm |
| Product Length | 181.1 mm |
| Sell Pack Quantity | 1 EA |
| Sell Pack Weight | 0.8528 kg |
| Sell Pack Width | 53.8 mm |
| Sell Pack Length | 53.8 mm |
| Sell Pack Height | 184.1 mm |
| Product group | Low Voltage UL/CSA Fuses |
| Body/Insulating Material | GMG |
| Product Weight | 0.8119 kg |
| HS Code | 85361090 |
| Country of Manufacture | Mexico |
The HSJ400 provides high speed overcurrent protection for power semiconductor devices while also delivering Class J branch circuit protection.
The Mersen HSJ400 has a rated current of 400 A.
The fuse is rated for circuits operating at up to 600 V AC or 500 V DC.
The HSJ400 has a maximum AC interrupting capacity of 200 kA, making it suitable for industrial systems with high available fault currents.
The fuse uses brass blade terminals and is installed in compatible clip-mounted Class J fuse holders, fused switches or approved electrical equipment.
Mersen Amp-Trap HSJ fuses are widely selected by automation engineers, panel builders and equipment manufacturers requiring dependable branch circuit protection and rapid fault interruption for sensitive industrial power electronics.
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LED Controls is a specialist distributor of factory automation and industrial controls, supplying OEMs, machine builders, panel builders and end users throughout the UK and worldwide. As a trusted UK distributor for many of the world’s leading automation manufacturers, we provide industrial control products, technical expertise and bespoke automation solutions backed by outstanding customer service.
2025 has been a big year for LED Controls, and our blog has expanded accordingly. We've covered a wide range of topics across industrial control and factory automation this year. From core technology explainers and new product releases to panel building best practice...
2025 has been a big year for LED Controls, and our blog has expanded accordingly. We've covered a wide range of topics across industrial control and factory automation this year. From core technology explainers and new product releases to panel building best practice...