Mersen W331150 US143M2I UltraSafe three-pole fuse holder for 14 x 51 mm cylindrical fuse links, rated up to 50 A with visual blown fuse indication, two integrated microswitches and IP20 finger-safe protection.
£125.53
The Mersen W331150, catalogue number US143M2I, is a premium 3-pole UltraSafe™ cylindrical fuse holder designed for demanding industrial control panels, machinery and power distribution systems. It accepts 14 × 51 mm cylindrical fuse links and combines visual blown fuse indication with two integrated microswitches for comprehensive local and remote fuse monitoring.
Rated for fuse currents up to 50 A, the US143M2I supports operating voltages of up to 800 V AC and 1000 V DC (UL) and 750 V AC (IEC). Its robust thermoplastic construction, pressure-plate terminals and IP20 finger-safe design provide dependable performance while enhancing operator safety during installation and fuse replacement.
The integrated visual indicators allow blown fuses to be identified immediately, while the two built-in microswitches provide remote signalling to PLCs, HMIs or alarm systems. This combination helps reduce fault-finding time, minimise downtime and improve maintenance efficiency in modern industrial automation systems.
The Mersen W331150 securely mounts three 14 × 51 mm cylindrical fuse links, protecting industrial circuits against overloads and short circuits while providing continuous monitoring capability. The integrated visual indicators allow maintenance personnel to identify an operated fuse immediately without additional test equipment.
Its dual microswitch arrangement enables remote indication to PLCs, SCADA systems or alarm circuits, allowing rapid fault diagnosis and reducing machine downtime. Combined with the UltraSafe™ finger-safe construction, the US143M2I delivers outstanding performance in demanding industrial environments.
| Phase | Three Phase |
|---|---|
| Manufacturer | Mersen |
| Series | UltraSafe™ US14 |
| Item number | W331150 |
| Catalogue number | US143M2I |
| EAN / UPC | 0782001311124 |
| Product type | Cylindrical fuse holder with indicators and microswitches |
| Compatible fuse size | 14 × 51 mm |
| Number of poles | 3 |
| Maximum fuse current | 50 A |
| Rated voltage AC (UL) | 800 V AC |
| Rated voltage DC (UL) | 1000 V DC |
| Rated voltage AC (IEC) | 750 V AC |
| Frequency | 50 / 60 Hz |
| Rated insulation voltage | 1000 V |
| Rated impulse withstand voltage | 8 kV |
| Short-circuit current rating | 200 kA with suitable fuse |
| Indication system | Visual indicator and 2 integrated microswitches |
| Terminal type | Pressure plate |
| Mounting type | DIN rail to EN 60715 |
| Protection rating | IP20 |
| Housing material | Industrial thermoplastic |
| Product weight | Approx. 0.46 kg |
| Compliance | UL, CSA, IEC and RoHS compliant |
| HS Code | 85361050 |
| Country of Manufacture | Tunisia |
The W331150 is a three-pole UltraSafe™ fuse holder designed for 14 × 51 mm cylindrical fuse links, providing industrial circuit protection together with local and remote fuse monitoring.
US143M2I identifies a three-pole UltraSafe™ fuse holder fitted with visual blown fuse indicators and two integrated microswitches.
The holder accepts 14 × 51 mm cylindrical fuse links with ratings up to 50 A.
The W331150 is rated for 800 V AC and 1000 V DC under UL standards, together with a 750 V AC IEC rating.
The holder incorporates visual blown fuse indicators together with two integrated microswitches for remote signalling to PLCs, alarm systems and industrial monitoring equipment.
Mersen UltraSafe™ fuse holders are trusted by OEM manufacturers, electrical panel builders and industrial engineers for high-performance circuit protection, advanced monitoring capability and enhanced operator safety.
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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...