Mersen X331151 US143N UltraSafe 3-Pole + Neutral modular fuse holder for 14 x 51 mm cylindrical fuse-links, rated 50 A, 800 V AC UL and 1000 V DC UL with IP20 finger-safe protection.
£69.71
The Mersen X331151, catalogue number US143N, is a premium 3-Pole + Neutral modular fuse holder from the UltraSafe™ US14 series. Designed for industrial power distribution, machinery and semiconductor protection, it accepts standard 14 × 51 mm cylindrical fuse-links while providing dependable overcurrent protection in demanding electrical installations.
The US143N combines three fused phase poles with an integrated neutral conductor in a compact DIN rail-mounted assembly. Its finger-safe IP20 enclosure remains protected during fuse replacement, helping improve operator safety and simplify maintenance. The holder also supports optional microswitch accessories for remote fuse status indication where required.
Rated for up to 50 A, with voltage ratings of 800 V AC UL, 1000 V DC UL and 750 V AC/DC IEC, the X331151 is ideal for protecting industrial drives, UPS systems, power conversion equipment, switchboards and automation systems.
The UltraSafe™ US14 range provides secure housing for cylindrical fuse-links while maintaining finger-safe protection throughout installation and maintenance. The 3-Pole + Neutral arrangement enables three-phase circuits to be protected while providing a dedicated neutral conductor within the same modular assembly.
The X331151 is particularly well suited to industrial machinery, UPS systems, variable speed drives and power conversion equipment where compact, dependable fuse protection is required. Optional microswitch accessories can be added for remote fuse monitoring when required by the application.
| Phase | Three Phase |
|---|---|
| Manufacturer | Mersen |
| Series | UltraSafe™ US14 |
| Item number | X331151 |
| Catalogue number | US143N |
| Product type | Modular cylindrical fuse holder |
| Configuration | 3-Pole + Neutral |
| Fuse size | 14 × 51 mm |
| Maximum fuse rating | 50 A |
| Rated voltage AC (UL) | 800 V |
| Rated voltage DC (UL) | 1000 V |
| Rated voltage AC/DC (IEC) | 750 V |
| Frequency | 50 / 60 Hz |
| Short-circuit current rating | 100 kA |
| Protection rating | IP20 |
| Terminal type | Pressure plate |
| Terminal material | Tin-plated copper |
| Wiring range | #2 to #14 AWG |
| Tightening torque | 3.5 Nm |
| Rated insulation voltage | 690 V |
| Rated impulse withstand voltage | 8 kV |
| Housing material | Polyamide |
| Mounting type | DIN rail mounting to EN 60715 |
| Dimensions (H × W × D) | approx. 110.8 × 106 × 76.5 mm |
| Weight | approx. 0.60 kg |
| EAN / UPC | 0782001311049 |
| RoHS compliant | Yes |
| HS Code | 85361050 |
| Country of Manufacture | Tunisia |
The X331151 is a 3-Pole + Neutral modular fuse holder designed to house 14 × 51 mm cylindrical fuse-links for industrial overcurrent protection.
The fuse holder accepts standard 14 × 51 mm cylindrical fuse-links.
The US143N supports fuse-links rated up to 50 A.
Yes. The UltraSafe US14 range supports optional microswitch accessories to provide remote fuse status indication where required.
The fuse holder mounts directly onto a standard DIN rail using pressure plate terminals for secure electrical connections.
Mersen UltraSafe™ fuse holders are trusted by panel builders, OEM manufacturers and industrial engineers for dependable circuit protection, finger-safe operation and long-term reliability in demanding electrical installations.
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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...