Why Choose the Mersen Q331145 UltraSafe™ US143M Fuse Holder?
The Mersen Q331145, catalogue number US143M, is a robust three-pole modular fuse holder designed for 14 × 51 mm cylindrical fuse links. Part of the Mersen UltraSafe™ US14 series, it provides dependable overcurrent protection and convenient circuit isolation for industrial machinery, power distribution systems and electrical control panels.
This model includes an integrated microswitch indication system for remote fuse-status monitoring. The auxiliary signalling function allows an operated fuse to be reported to a PLC, alarm circuit or control system, helping maintenance teams locate faults quickly and reduce equipment downtime.
Rated at 50 A, the Q331145 supports applications up to 800 V AC and 1000 V DC under UL ratings, as well as up to 750 V AC or DC under IEC ratings. Its IP20 finger-safe polyamide housing, pressure-plate connections and DIN rail mounting format provide safe, efficient installation in demanding industrial environments.
Key Advantages
- Reliable three-pole modular fuse holder for industrial circuit protection.
- Designed for standard 14 × 51 mm cylindrical fuse links.
- 50 A maximum fuse rating.
- Integrated microswitch for remote fuse-status indication.
- Rated up to 800 V AC and 1000 V DC under UL standards.
- Finger-safe IP20 protection, including during fuse replacement.
- 100 kA short-circuit current rating when used with suitable fuse links.
- DIN rail mounting supports fast and convenient panel installation.
Key Features
- Mersen UltraSafe™ US14 series.
- US143M catalogue designation.
- Three-pole configuration.
- Compatible with 14 × 51 mm cylindrical fuse links.
- 50 A rated current.
- 800 V AC and 1000 V DC UL ratings.
- 750 V AC and 750 V DC IEC ratings.
- Integrated remote indication microswitch.
- Durable polyamide insulating housing.
- DIN rail mounting in accordance with EN 60715.
Reliable Three-Phase Protection with Remote Indication
The Mersen Q331145 securely accommodates three cylindrical fuse links, providing effective protection against overload and short-circuit conditions when fitted with correctly selected fuses. Its three-pole configuration makes it suitable for coordinated protection and isolation within three-phase industrial electrical systems.
The integrated microswitch enables remote fuse-status signalling, allowing maintenance teams or automation systems to identify an operated fuse without relying solely on manual inspection. Combined with its finger-safe construction and high voltage capability, the US143M is well suited to applications where safety, reliability and rapid fault diagnosis are essential.
Typical Applications
- Industrial control panels.
- Three-phase power distribution systems.
- Motor control centres.
- Variable speed drive protection.
- Transformer protection.
- OEM machinery and automation systems.
- Renewable energy installations.
- Industrial AC and DC switchboards.
