Mersen N331143 UltraSafe US143 three-pole modular fuse holder for 14×51 mm cylindrical fuse links, with pressure-plate terminals, IP20 protection and applicable ratings up to 800 V AC and 1000 V DC.
£48.21
The Mersen N331143, catalogue reference US143, is a robust UltraSafe™ modular fuse holder designed for 14×51 mm cylindrical fuse links. Its three-pole configuration provides coordinated fuse protection and circuit isolation for three-phase industrial electrical systems.
Part of the Mersen UltraSafe™ US14 range, the N331143 features a durable polyamide housing and finger-safe IP20 protection, including during fuse replacement. This helps protect personnel from accidental contact with live components while supporting safe and efficient panel maintenance.
The holder supports fuse currents up to 50 A and is rated for systems up to 800 V AC and 1,000 V DC under applicable UL ratings. Its pressure-plate terminals and DIN rail mounting format provide secure conductor connections and straightforward installation in control panels, machinery and power distribution equipment.
The Mersen N331143 securely houses three 14×51 mm cylindrical fuse links, allowing correctly selected fuses to protect three-phase circuits against overload and short-circuit conditions. Its linked three-pole construction enables convenient operation and maintenance across all three protected phases.
The UltraSafe™ design maintains IP20 finger-safe protection during normal operation and fuse replacement. Combined with robust construction and secure pressure-plate terminals, this makes the holder well suited to demanding industrial AC and DC installations.
| Phase | Three Phase |
|---|---|
| Manufacturer | Mersen |
| Series | UltraSafe™ US14 |
| Item number | N331143 |
| Catalogue number | US143 |
| Product type | Modular cylindrical fuse holder |
| Fuse size | 14 × 51 mm |
| Number of poles | 3 |
| Conventional free-air thermal current | 50 A |
| Rated voltage AC UL | 800 V AC |
| Rated voltage DC UL | 1,000 V DC |
| Frequency | 50 / 60 Hz |
| Terminal type | Pressure plate |
| Fuse indication | No integrated visual indicator |
| Protection rating | IP20 |
| Mounting type | DIN rail mounting to EN 60715 |
| Insulating body material | Polyamide |
| Dimensions (H × W × D) | Approx. 110.8 × 79.5 × 76.5 mm |
| Product weight | Approx. 0.43 kg |
| EAN / UPC | 0782001311032 |
| HS Code | 85361050 |
| Country of Manufacture | Tunisia |
The Mersen N331143 is a three-pole modular fuse holder used with 14×51 mm cylindrical fuse links to protect three-phase industrial AC and DC electrical circuits.
The N331143 is designed specifically for 14×51 mm cylindrical fuse links.
The holder supports fuse currents up to 50 A and has applicable UL voltage ratings of up to 800 V AC and 1,000 V DC.
No. The US143 is the standard version without an integrated visual blown fuse indicator.
It mounts onto a standard DIN rail in accordance with EN 60715 and uses pressure-plate terminals for secure conductor connection.
Mersen UltraSafe™ fuse holders are trusted by panel builders, OEMs and electrical engineers for dependable circuit protection, finger-safe operation and reliable performance across demanding industrial 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...