Why Choose the Mersen N331143 UltraSafe™ US143 Fuse Holder?
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.
Key Advantages
- Designed for 14×51 mm cylindrical fuse links.
- Three-pole configuration for three-phase circuit protection.
- Supports fuse currents up to 50 A.
- Rated for systems up to 800 V AC and 1,000 V DC.
- Finger-safe IP20 protection, including during fuse replacement.
- Pressure-plate terminals provide secure conductor connections.
- DIN rail mounting simplifies installation in electrical panels.
- Durable polyamide construction offers excellent mechanical and thermal performance.
Key Features
- Mersen UltraSafe™ US14 series.
- Manufacturer item number N331143.
- Catalogue number US143.
- Accepts 14×51 mm cylindrical fuse links.
- Three-pole modular construction.
- 50 A conventional free-air thermal current with fuse links.
- 800 V AC UL rated voltage.
- 1,000 V DC UL rated voltage.
- Pressure-plate terminal connection.
- IP20 finger-safe protection.
- DIN rail mounting to EN 60715.
- Standard version without an integrated visual fuse indicator.
Safe Three-Phase Fuse Protection
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.
Typical Applications
- Three-phase industrial control panels.
- Motor and machinery protection circuits.
- Industrial power distribution equipment.
- Variable speed drive installations.
- Renewable energy and DC systems.
- OEM machinery and automation equipment.
- Electrical switchboards and enclosures.
