Mersen Amp-Trap® OTM Midget Fa...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$9.54
Mersen Amp-Trap® OTM Midget Fast-Acting Ferrule Fuse, 250VAC

Mersen Amp-Trap® OTM Midget Fast-Acting Ferrule Fuse, 250VAC

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Model: OTM3

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

$9.54
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Mersen Amp-Trap® OTM Midget Fast-Acting Ferrule Fuse, 250VAC

The Mersen Amp-Trap® OTM Midget fuse is a One-Time, fast-acting fuse rated 250VAC, engineered to deliver dependable, low-cost overcurrent protection for general purpose lighting, heating, and control circuits where a time-delay characteristic is not required. Built with a compact Midget-class body, Ferrule connection/terminal type for fuse-clip mounting, Tin-Plated Copper terminals, and Paper insulating material, this fuse offers a reliable, code-compliant option for panels and equipment calling for standard 250VAC Midget fuses. With an AC Max Interrupting Rating of 10 kA and a 50/60 Hz frequency rating, the Amp-Trap® OTM Midget series suits a wide range of commercial and industrial low-voltage circuits. This fuse is not intended for Branch Circuit Protection.

Key Features

  • Fast-Acting Characteristic: One-Time, non-time-delay operation for circuits requiring instantaneous overcurrent clearing without the added cost of time-delay engineering.
  • Ferrule Terminals: Ferrule connection/terminal type with Tin-Plated Copper construction for reliable, low-resistance contact when mounted in standard fuse clips.
  • Midget Fuse Class: Compact Midget-class body with Paper insulating material, sized for space-constrained panels, disconnects, and fuse holders.
  • 250VAC Rated Voltage (UL): Rated 250 V AC per UL for general purpose lighting, heating, and control circuit applications.
  • 10 kA Interrupting Capacity: AC Max I.R./Breaking Capacity (I1) of 10 kA delivers dependable fault-current interruption within the fuse's rated duty.
  • 50/60 Hz Frequency Rating: Compatible with standard 50/60 Hz AC power systems used in commercial and industrial facilities.
  • Clip Mounting: Designed for straightforward installation and replacement in compatible Midget fuse holders and fuse blocks.
  • RoHS Compliant: Manufactured to meet RoHS restricted-substance requirements for electrical and electronic components.

Certifications & Compliance

  • RoHS Compliant
  • Rated Voltage AC per UL: 250 V

Technical Specifications

  • AC or DC: AC
  • Ampere Rating: 6 A
  • RoHS Compliant: Yes

Typical Applications

  • General Purpose Lighting Circuits
  • Heating Circuits
  • Control Circuits and Control Panels
  • Commercial and Industrial Electrical Equipment
  • Fuse Clip / Ferrule Holder Assemblies
  • Replacement Fuse for Existing 250VAC Midget Fuse Installations

Why Mersen?

Mersen Amp-Trap® OTM Midget fuses combine a Tin-Plated Copper ferrule terminal design with a Paper-insulated Midget-class body to deliver consistent, fast-acting overcurrent protection for general purpose lighting, heating, and control circuits. With a 10 kA AC interrupting rating, a 250VAC UL voltage rating, 50/60 Hz frequency compatibility, and RoHS compliance, these Amp-Trap® OTM fuses support code-compliant, dependable performance for professional electrical work where straightforward, low-cost fuse protection is required.

Manufacturer Resources

Product Specs

Product Type:
Fuse
Product Material:
Paper
Product Finish:
Tin-Plated Copper
Connection Type:
Ferrule
Voltage Rating:
250VAC
Amperage Rating:
6A
Standards:
RoHS Compliant
Department:
Electrical
Product Group:
Wiring Devices

Mersen OTM3 – Frequently Asked Questions

1) Will a Mersen OTM midget fuse fit my existing fuse clips?
The Amp-Trap OTM is a ferrule fuse, so it drops into standard midget fuse clips and clip-style holders rather than blocks that need a bolt-on or blade termination. Terminals are tin-plated copper for low-resistance contact in the clip. If your holder takes a screw-terminal or knife-blade fuse, the OTM is not the right body style.
2) Can I use a Mersen OTM fuse for branch circuit protection?
No. The OTM midget is a supplementary fuse and is not intended for branch circuit protection. Use it for general purpose lighting, heating, and control circuits inside panels and equipment. If the NEC requires branch circuit protection at that point in your system, you need a listed branch circuit fuse class instead, not a midget OTM.
3) Is the Mersen OTM a fast-acting or time-delay fuse?
Fast-acting, one-time, with no time delay. That makes it right for lighting, heating, and control circuits that draw no meaningful inrush. On a motor, transformer primary, or anything with a magnetizing or starting surge, a fast-acting midget will open on normal startup current. Those loads want a time-delay midget instead.
4) Can I put a 250VAC Mersen OTM fuse on a 480V circuit?
No. The OTM carries a 250VAC UL voltage rating, which is a ceiling, not a target. It is fine on 120V and 208/240V circuits and on control transformer secondaries at or below 250 volts, but applying it above its rating risks the arc failing to clear. For a 480V circuit you need a 600V-rated midget.
5) I am replacing a blown midget fuse in a control panel. How do I pick the right OTM?
Match three things off the old fuse: the amp rating, the voltage rating, and the characteristic. If the fuse coming out is a fast-acting midget rated 250V or less, order the OTM in the same amperage, 1A through 20A. If the old one is marked time-delay or dual-element, do not swap in an OTM, it will nuisance-open. If it is marked 600V, the 250VAC OTM is not a substitute.
6) Can a Square D PowerLogic energy meter fuse pack be used in place of a Mersen Amp-Trap OTM midget fuse?
No - they are built for different jobs. The Square D PowerLogic Energy Meter Fuse Pack is a set of three 0.5A 600V fuses sold for metering duty on PowerLogic energy meters, so it protects the meter's voltage-sensing leads at a fixed half-amp rating. The Mersen Amp-Trap OTM is a 250VAC one-time fast-acting midget fuse with ferrule terminals, made for general purpose lighting, heating, and control circuits, and it is offered from 1A up to 20A. If the fuse you are pulling out came from a PowerLogic meter, replace it with the meter fuse pack; if it is a 250VAC midget in a fuse clip on a lighting, heating, or control circuit, the OTM is the family to size from.
7) What amp ratings does the Mersen OTM midget fuse come in?
The OTM series is stocked in 1A, 2A, 3A, 4A, 5A, 6A, 10A, 15A, and 20A. The catalog number follows the amp rating directly, so a 6 amp is OTM6 and a 20 amp is OTM20. All share the same 250VAC rating and midget ferrule body, so you can standardize a control panel on one holder and stock several ratings behind it.
8) What is the interrupting rating of the Mersen OTM midget fuse?
10 kA AC interrupting rating at 250VAC. That is the fault current the fuse can safely clear, so check it against the available fault current at the point of installation. On a control circuit fed from a small transformer, 10 kA is comfortably above anything the transformer can deliver. On a circuit close to a large service where available fault current runs higher, you need a fuse with a higher interrupting rating.
9) Will a Mersen OTM work on a 50 Hz system in an imported machine?
Yes. The OTM is rated 50/60 Hz, so it works in equipment built for either standard, provided the circuit voltage is 250VAC or less. AC only, though. Do not apply it on a DC control circuit.
10) Are Mersen OTM fuses RoHS compliant for a spec that requires it?
Yes, the OTM midget series is manufactured to RoHS restricted-substance requirements, which covers the common institutional and OEM submittal requirement. The body uses paper insulating material with tin-plated copper ferrules.
How fast can I get the Mersen OTM3 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 OTM3 come with a warranty?
Absolutely. The Mersen OTM3 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 OTM3?
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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