Mersen J331139 UltraSafe US142M 2-pole modular fuse holder for 14 × 51 mm cylindrical fuse-links with two auxiliary microswitches, 50 A rating, DIN rail mounting and IP20 finger-safe protection.
£67.43
The Mersen J331139, catalogue number US142M, is a premium 2-pole UltraSafe™ modular fuse holder designed for protecting industrial power distribution, machinery and electrical control systems. It accepts standard 14 × 51 mm cylindrical fuse-links and incorporates two auxiliary microswitches to provide reliable remote fuse-status indication for automation and monitoring systems.
Part of the advanced Mersen UltraSafe™ US14 range, the US142M features a robust finger-safe IP20 housing, pressure-plate terminals and DIN rail mounting. Its modular construction simplifies installation while providing secure electrical connections and dependable long-term performance in demanding industrial environments.
Rated at 50 A, with 800 V AC and 1000 V DC UL ratings, the J331139 is ideal for motor protection, transformers, industrial automation, variable speed drives and power conversion equipment where remote monitoring of fuse operation is required.
The Mersen J331139 securely accommodates two 14 × 51 mm cylindrical fuse-links while providing remote signalling through its integrated auxiliary microswitches. When a compatible fuse operates, the microswitches can be connected to PLCs, alarms or SCADA systems to provide rapid fault notification and reduce machine downtime.
Its compact UltraSafe™ construction combines excellent operator safety with high electrical performance, making it an ideal choice for industrial machinery, power distribution systems and automation equipment requiring dependable overcurrent protection and remote diagnostics.
| Manufacturer | Mersen |
|---|---|
| Series | UltraSafe™ US14 |
| Catalogue number | US142M |
| Manufacturer part number | J331139 |
| Product type | Modular cylindrical fuse holder |
| Fuse size | 14 × 51 mm |
| Number of poles | 2 |
| Rated current | 50 A |
| Rated voltage AC | 800 V UL |
| Rated voltage DC | 1000 V UL |
| IEC rated voltage | 690 V AC / DC |
| Short-circuit current rating | 200 kA |
| Auxiliary contacts | Two integrated microswitches |
| Connection type | Pressure plate terminals |
| Protection rating | IP20 |
| Mounting type | DIN rail |
| Housing material | Polyamide thermoplastic |
| Dimensions (H × W × D) | Approx. 111 × 53 × 76 mm |
| Weight | Approx. 0.31 kg |
| RoHS compliant | Yes |
| HS Code | 85361050 |
| Country of Manufacture | Tunisia |
The J331139 accepts standard 14 × 51 mm cylindrical fuse-links.
The two auxiliary microswitches provide remote fuse-status indication for PLCs, alarm systems and industrial monitoring equipment.
The fuse holder is rated at 50 A, up to 800 V AC and 1000 V DC under UL ratings, with IEC ratings up to 690 V AC/DC.
Yes. The UltraSafe™ design provides IP20 finger-safe protection, including during fuse replacement.
The fuse holder mounts directly onto a standard DIN rail using its modular housing for quick installation inside electrical control panels.
Mersen UltraSafe™ fuse holders are trusted worldwide by panel builders, OEM manufacturers and industrial engineers for dependable circuit protection, remote fuse monitoring and long-term reliability in demanding electrical installations.
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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...