Mersen USM Series UltraSafe Mi...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$84.33
Mersen USM Series UltraSafe Midget Fuse Holder with LED Indication

Mersen USM Series UltraSafe Midget Fuse Holder with LED Indication

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Model: USM1I-DC24

In Stock (leaves warehouse same day if ordered before 3pm ET)

$84.33
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Mersen USM1I UltraSafe Midget Fuse Holder, 600VAC/600VDC 30A, 1-Pole, LED Indication

The Mersen USM1I UltraSafe Midget Fuse Holder is a professional-grade, DIN rail mounted, 1-Pole fuse holder rated 600VAC/600VDC at 30A, built for reliable circuit protection in industrial and commercial electrical systems. Durable polyamide insulating material and an integrated LED indication system give at-a-glance fuse status monitoring, backed by a 100 kA short circuit current rating (SCCR) for demanding fault-current environments. Clip-in fuse installation and a wiring range of #6 to #14 solid or stranded conductors make it fast to install and maintain on standard DIN rail panels.

Key Features

  • Dual Voltage Rating: 600VAC/600VDC rated for versatile AC and DC circuit protection applications.
  • 30A Ampere Rating: Max fuse rating of 30A suited to medium-duty electrical circuits and equipment.
  • 1-Pole Configuration: Single-pole design for straightforward panel and control cabinet wiring.
  • LED Indication System: Integrated LED provides immediate visual fuse status for quick troubleshooting.
  • DIN Rail Mounting: Enables fast, secure installation in standard electrical panels and control cabinets.
  • Polyamide Insulating Material: Durable, reliable electrical isolation for demanding environments.
  • 100 kA Short Circuit Current Rating: Exceptional fault current interruption capability.
  • Clip-in Fuse Installation: Quick, tool-free midget fuse replacement for efficient maintenance.
  • Wiring Range: Accepts #6 to #14 AWG solid or stranded conductors, torqued to 15 lb-in.

Certifications & Compliance

  • RoHS Compliant

Technical Specifications

  • Ac Or Dc: AC/DC
  • Ampere Rating: 30 A
  • Body Insulating Material: Polyamide
  • Frequency Hz: 50/60 Hz
  • Fuse Class: Midget
  • Fuse Installation Method: Clip-in
  • Indication System: Yes
  • Indication System Type: LED
  • Number Of Poles: 1-Pole
  • Rated Voltage AC UL: 600 V
  • Rated Voltage DC UL: 600 V
  • Rohs Compliant: Yes
  • Short Circuit Current Rating (SCCR): 100 kA
  • Torque Rating: 15 lb-in
  • Wiring Range: #6 to #14 Solid or Stranded
  • Product Height: 2.32 in
  • Product Length: 3.07 in
  • Product Width: 0.69 in
  • Product Weight: 0.14 lb

Typical Applications

  • Industrial Control Panels and Motor Control Centers
  • Commercial Electrical Distribution Systems
  • Manufacturing Equipment Protection
  • Process Control and Automation Systems
  • Power Distribution Panels

Why Mersen?

Mersen UltraSafe fuse holders combine proven reliability with professional-grade construction, featuring RoHS compliant polyamide insulation and a robust 100 kA short circuit current rating. The integrated LED indication system and DIN rail mounting deliver the convenience and code-compliant performance electrical professionals demand.

Manufacturer Resources

Product Specs

Product Group:
Wiring Devices
Ampere Rating:
30 A
Torque Rating:
15 lb-in
Indication System Type:
LED
Department:
Electrical
Fuse Class:
Midget
Fuse Installation Method:
Clip-in
Max Fuse Rating:
30 A
Installation Mounting:
DIN Rail
Product Type:
Fuse Holder

Mersen USM1I-DC24 – Frequently Asked Questions

1) What size fuse does the Mersen USM UltraSafe holder take?
It takes midget class fuses, clip-in style, up to 30 A. Midget fuses are the 13/32 x 1-1/2 inch size, so a class CC or comparable midget-body fuse drops straight in. Anything larger (class J, class CC blocks with rejection, or ferrule fuses of other lengths) will not seat in these clips.
2) Can I use the Mersen USM1I fuse holder on a DC circuit?
Yes. The USM1I is rated 600 V AC and 600 V DC, at 50/60 Hz on the AC side, so it works in solar, battery, and drive DC circuits as well as standard AC control power.
3) Which Mersen USM part number do I order for a three phase circuit?
For three phase, order USM3I, the 3-pole version. Single phase line and neutral or a two wire DC circuit takes USM2I (2-pole), and a single ungrounded conductor takes USM1I (1-pole). There is also USM1I-DC24, the 24 V DC indication variant.
4) Is the Mersen USM holder rated for a 100 kA fault current panel?
Yes, the UltraSafe USM carries a 100 kA short circuit current rating, which is what you need when a panel's available fault current is high. Note the SCCR is the holder plus a properly rated midget fuse; the fuse is what does the interrupting.
5) Can a Littelfuse WPB1 in-line fuse holder be used instead of the Mersen USM midget fuse holder?
They solve different problems. The Mersen USM UltraSafe holder mounts on DIN rail inside a panel or control cabinet, takes midget fuses by clip-in, and carries an LED fuse status indicator, with terminals torqued to 15 lb-in. The Littelfuse WPB1 is an in-line watertight fuse holder, meaning it is spliced into a cable run rather than mounted to rail, and is the choice where the fuse sits outside an enclosure in a wet or exposed location. If the fuse belongs in a control panel with visual status at the door, use the USM; if it belongs in the harness, use the in-line style.
6) How does the Mersen USM fuse holder mount in a panel?
It snaps onto standard DIN rail, so it goes into a control cabinet or distribution panel alongside your breakers and terminal blocks with no drilling or screw feet. Body dimensions are 3.07 x 2.32 x 0.69 in, which means each pole eats about 0.69 in of rail width.
7) Do I need a separate blown fuse indicator with the Mersen USM1I?
No. LED indication is built into the holder, so a blown fuse shows at a glance without opening the circuit or pulling the carrier to test it. That is the difference between the USM-I models and a plain USM holder.
8) I need a fuse holder for an outdoor or wet location, not a panel. Is this the right one?
No. The DIN rail mounted USM is built for enclosed control panels and distribution cabinets. For an exposed or wet run, look at the Littelfuse WPB1 Series in-line watertight fuse holder instead.
9) Is a Littelfuse LSRY plug fuse box cover unit an alternative to the Mersen USM fuse holder?
No, they serve different circuits. The Littelfuse LSRY is a plug fuse box cover unit rated 125V 15A, intended to fuse a branch circuit at a box cover using a screw-in plug fuse. The Mersen USM UltraSafe holder is a DIN rail fuse holder for midget fuses rated up to 30 A, built for industrial control panels and motor control centers, with an LED that shows fuse status without opening the holder. Fuse body style, mounting, and the ratings each supports are all different, so one does not drop in for the other.
10) For a wet or outdoor fuse location, what should be used instead of the Mersen USM holder?
The Mersen USM UltraSafe midget holder is a DIN rail device with a polyamide body sized for panel and control cabinet interiors, so it depends on the enclosure for its environmental protection. Where the fuse sits outside an enclosure and has to survive moisture directly, the Littelfuse WPB1 in-line watertight fuse holder is the style built for that placement. Keep the USM for the panel work and specify the watertight in-line holder for the exposed run.
11) What is the body made of on the Mersen UltraSafe midget fuse holder, and is it RoHS compliant?
The insulating body is polyamide, and the holder is RoHS compliant. Polyamide is the standard choice for control panel fuse holders where heat and mechanical handling during fuse changes are routine.
12) Will a Mersen USM work for a 120 V plug fuse application?
No. The USM is a 600 V midget clip-in holder for DIN rail. Plug fuse work, such as a 125 V 15 A box cover unit, is a different animal; the Littelfuse LSRY Series plug fuse box cover unit covers that case.
How fast can I get the Mersen USM1I-DC24 delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the continental U.S. Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the Mersen USM1I-DC24 come with a warranty?
Absolutely. The Mersen USM1I-DC24 is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the Mersen USM1I-DC24?
You can call, text, or email our expert support team for fast answers. We’re here to help with product selection, installation tips, and troubleshooting. Contact Us
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