Mersen K331140 US142MI UltraSafe two-pole modular fuse holder for 14 x 51 mm cylindrical fuse links, rated 50 A with visual blown-fuse indication, auxiliary microswitch and IP20 protection.
£92.30
The Mersen K331140, catalogue reference US142MI, is a robust two-pole modular fuse holder designed for 14 × 51 mm cylindrical fuse links. Part of the Mersen UltraSafe™ US14 series, it provides dependable overcurrent protection for industrial control, power distribution and equipment protection applications.
This fuse holder combines a visual blown-fuse indicator with auxiliary microswitch functionality, helping maintenance teams identify operated fuse links and remotely monitor fuse or holder status. Its finger-safe IP20 construction improves protection during installation, operation and fuse replacement.
Rated for currents up to 50 A, the K331140 supports IEC voltages up to 750 V AC/DC and UL ratings of 800 V AC and 1000 V DC. Its compact DIN rail mounted format, durable polyamide body and pressure-plate terminals make it suitable for demanding electrical panels and machinery.
The Mersen K331140 provides a secure and convenient method of installing cylindrical fuse links within electrical control panels and distribution equipment. The two-pole configuration allows two conductors or phases to be protected within one compact modular device.
Its visual indicator helps personnel quickly identify a blown fuse when the circuit remains energised. The auxiliary microswitch can also provide remote signalling for fuse operation, holder opening or fuse presence, depending on the circuit design and fuse link used.
| Manufacturer | Mersen |
|---|---|
| Series | UltraSafe™ US14 |
| Catalogue number | US142MI |
| Item number | K331140 |
| Product type | Modular cylindrical fuse holder |
| Number of poles | 2 |
| Fuse size | 14 × 51 mm |
| Maximum fuse rating | 50 A |
| Rated voltage, IEC | 750 V AC / 750 V DC |
| Rated voltage, UL | 800 V AC / 1000 V DC |
| Rated insulation voltage | 690 V |
| Rated impulse withstand voltage | 8 kV |
| Short-circuit current rating | 100 kA |
| Frequency | 50 / 60 Hz |
| Indication | Visual indicator and auxiliary microswitch |
| Protection rating | IP20 |
| Mounting type | DIN rail to EN 60715 |
| Terminal type | Pressure plate / clip connection |
| Terminal material | Tin-plated copper |
| Rigid conductor range | 1.5–35 mm² |
| Stranded conductor range | 1.5–25 mm² |
| Maximum tightening torque | 3.5 Nm |
| Body material | Polyamide |
| Operating temperature | -25°C to +60°C |
| Dimensions (H × W × D) | approx. 110.7 × 53.1 × 76.5 mm |
| Weight | approx. 0.31 kg |
| Compliance | UL 4248, CSA C22.2, IEC 60269-2, IEC 60947-3 and RoHS |
| HS Code | 85361050 |
| Country of Manufacture | Tunisia |
The K331140 is a two-pole modular fuse holder used to install 14 × 51 mm cylindrical fuse links in industrial AC and DC circuit protection applications.
It is designed for standard 14 × 51 mm cylindrical fuse links with a maximum fuse rating of 50 A.
Yes. The US142MI includes a visual blown-fuse indicator and auxiliary microswitch functionality for local and remote status monitoring.
It is rated up to 750 V AC/DC under IEC standards, with UL ratings of 800 V AC and 1000 V DC.
The fuse holder mounts onto a standard DIN rail in accordance with EN 60715 and uses pressure-plate terminals for secure conductor connections.
Mersen UltraSafe™ fuse holders are widely specified by electrical engineers, OEM manufacturers and panel builders for reliable circuit protection, finger-safe operation and efficient maintenance in demanding 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...