MERSEN FUSE US142M US142M

Q: What fuse size does the Mersen J331139 accept?

The J331139 accepts standard 14 × 51 mm cylindrical fuse-links.

Q: What are the electrical ratings of the US142M?

The fuse holder is rated at 50 A, up to 800 V AC and 1000 V DC under UL ratings, with IEC ratings up to 690 V AC/DC.

Q: Is the J331139 finger-safe?

Yes. The UltraSafe™ design provides IP20 finger-safe protection, including during fuse replacement.

Mersen J331139 UltraSafe US142M 2-pole modular fuse holder for 14 × 51 mm cylindrical fuse-links with two auxiliary microswitches, 50 A rating, DIN rail mounting and IP20 finger-safe protection.

SKU: J331139Alt SKU: US142MMPN: J331139

List Price £67.43 ex VAT

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Why Choose the Mersen J331139 UltraSafe™ US142M Fuse Holder?

The Mersen J331139, catalogue number US142M, is a premium 2-pole UltraSafe™ modular fuse holder designed for protecting industrial power distribution, machinery and electrical control systems. It accepts standard 14 × 51 mm cylindrical fuse-links and incorporates two auxiliary microswitches to provide reliable remote fuse-status indication for automation and monitoring systems.

Part of the advanced Mersen UltraSafe™ US14 range, the US142M features a robust finger-safe IP20 housing, pressure-plate terminals and DIN rail mounting. Its modular construction simplifies installation while providing secure electrical connections and dependable long-term performance in demanding industrial environments.

Rated at 50 A, with 800 V AC and 1000 V DC UL ratings, the J331139 is ideal for motor protection, transformers, industrial automation, variable speed drives and power conversion equipment where remote monitoring of fuse operation is required.

Key Advantages

Designed for 14 × 51 mm cylindrical fuse-links.
2-pole configuration for industrial AC and DC circuits.
Integrated two auxiliary microswitches for remote fuse monitoring.
50 A current rating.
Suitable for systems up to 800 V AC and 1000 V DC.
IP20 finger-safe protection during operation and fuse replacement.
Compact DIN rail mounting saves valuable panel space.

Key Features

Mersen UltraSafe™ US14 series.
Catalogue number: US142M.
Manufacturer part number: J331139.
2-pole modular fuse holder.
Compatible with 14 × 51 mm cylindrical fuse-links.
50 A conventional free-air thermal current.
800 V AC / 1000 V DC UL ratings.
Two integrated auxiliary microswitches.
Pressure-plate terminal connections.
DIN rail mounting.
IP20 finger-safe construction.
Lockable, sealable modular design.

Reliable Circuit Protection with Remote Monitoring

The Mersen J331139 securely accommodates two 14 × 51 mm cylindrical fuse-links while providing remote signalling through its integrated auxiliary microswitches. When a compatible fuse operates, the microswitches can be connected to PLCs, alarms or SCADA systems to provide rapid fault notification and reduce machine downtime.

Its compact UltraSafe™ construction combines excellent operator safety with high electrical performance, making it an ideal choice for industrial machinery, power distribution systems and automation equipment requiring dependable overcurrent protection and remote diagnostics.

Typical Applications

Industrial control panels.
Variable speed drives.
Motor and transformer protection.
Power conversion equipment.
Industrial automation systems.
PLC monitoring circuits.
OEM machinery.
Low-voltage power distribution.

Technical Specifications

Manufacturer	Mersen
Series	UltraSafe™ US14
Catalogue number	US142M
Manufacturer part number	J331139
Product type	Modular cylindrical fuse holder
Fuse size	14 × 51 mm
Number of poles	2
Rated current	50 A
Rated voltage AC	800 V UL
Rated voltage DC	1000 V UL
IEC rated voltage	690 V AC / DC
Short-circuit current rating	200 kA
Auxiliary contacts	Two integrated microswitches
Connection type	Pressure plate terminals
Protection rating	IP20
Mounting type	DIN rail
Housing material	Polyamide thermoplastic
Dimensions (H × W × D)	Approx. 111 × 53 × 76 mm
Weight	Approx. 0.31 kg
RoHS compliant	Yes
HS Code	85361050
Country of Manufacture	Tunisia
Poles	2-pole
Device Type	Fuse base / holder
Fuse Type	Cylindrical
Fuse Size	14x51 mm
Current	50 A
Voltage	800 V

Frequently Asked Questions

What fuse size does the Mersen J331139 accept?

The J331139 accepts standard 14 × 51 mm cylindrical fuse-links.

What is the purpose of the integrated microswitches?

The two auxiliary microswitches provide remote fuse-status indication for PLCs, alarm systems and industrial monitoring equipment.

What are the electrical ratings of the US142M?

The fuse holder is rated at 50 A, up to 800 V AC and 1000 V DC under UL ratings, with IEC ratings up to 690 V AC/DC.

Is the J331139 finger-safe?

Yes. The UltraSafe™ design provides IP20 finger-safe protection, including during fuse replacement.

How is the Mersen J331139 installed?

The fuse holder mounts directly onto a standard DIN rail using its modular housing for quick installation inside electrical control panels.

Trusted by Industrial Electrical Professionals

Mersen UltraSafe™ fuse holders are trusted worldwide by panel builders, OEM manufacturers and industrial engineers for dependable circuit protection, remote fuse monitoring and long-term reliability in demanding electrical installations.

Manufacturer	Mersen
Series	UltraSafe™ US14
Catalogue number	US142M
Manufacturer part number	J331139
Product type	Modular cylindrical fuse holder
Fuse size	14 × 51 mm
Number of poles	2
Rated current	50 A
Rated voltage AC	800 V UL
Rated voltage DC	1000 V UL
IEC rated voltage	690 V AC / DC
Short-circuit current rating	200 kA
Auxiliary contacts	Two integrated microswitches
Connection type	Pressure plate terminals
Protection rating	IP20
Mounting type	DIN rail
Housing material	Polyamide thermoplastic
Dimensions (H × W × D)	Approx. 111 × 53 × 76 mm
Weight	Approx. 0.31 kg
RoHS compliant	Yes
HS Code	85361050
Country of Manufacture	Tunisia
Poles	2-pole
Device Type	Fuse base / holder
Fuse Type	Cylindrical
Fuse Size	14x51 mm
Current	50 A
Voltage	800 V

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