Bussmann FNM Series Fusetron D...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$14.03
Bussmann FNM Series Fusetron Dual-Element Time-Delay Midget Fuse

Bussmann FNM Series Fusetron Dual-Element Time-Delay Midget Fuse

(No reviews yet) Write a Review

Model: FNM-20

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

$14.03
Adding to cart… The item has been added
Free Shipping on orders over $199
We price match and offer bulk discounts! Click Add to Quote. It's quick and easy.
✨
Earn points with this purchase! You can redeem points for giftcards, iPads, XBox's and more. View Rewards
Free Keying on all locks
You may also like

Bussmann FNM Series Fusetron Dual-Element Time-Delay Midget Fuse

The Bussmann FNM Series is a line of Fusetron dual-element, time-delay midget fuses rated 250-Volt AC and available in amperage ratings from 15 Amp to 20 Amp, designed for non-rejection style fuse holders and fuse blocks. Identified in the manufacturer catalog as Miniature Fusetron fuses, the FNM Series pairs a fast-acting short-circuit element with a thermal time-delay element so the fuse can ride through momentary inrush current and temporary overloads without opening unnecessarily. This dual-element construction makes the FNM Series a practical choice for control circuits, small motor loads, and other applications where a standard fast-blow fuse would nuisance-trip. FNM Series fuses are commonly specified as a like-for-like replacement for OEM equipment originally supplied with Fusetron-branded fuses of the same voltage class.

Key Features

  • Amperage Rating Range: Available in 15 Amp and 20 Amp ratings sized for control circuits, small motor branch circuits, and other moderate current loads.
  • Voltage Rating: 250-Volt AC rating suitable for standard low-voltage power distribution circuits across the FNM Series.
  • Dual-Element Construction: Combines a spring-loaded short-circuit element with a thermal time-delay element to absorb temporary overloads and inrush current.
  • Time-Delay Operation: Fusetron time-delay design reduces nuisance opening on circuits with motor starting current or transformer inrush.
  • Midget Fuse Body: Compact Miniature Fusetron-class body style sized to fit midget fuse blocks and holders.
  • Non-Rejection Style: Ferrule configuration designed to fit standard non-rejection fuse clips, holders, and blocks.
  • Fusetron Series: Part of the Bussmann Fusetron line of dual-element, time-delay fuses, with the FNM designator shared across the amperage range.
  • Reliable Overcurrent Protection: Time-delay dual-element design helps protect wiring and equipment while avoiding unnecessary fuse replacement from temporary current spikes.

Technical Specifications

  • Amperage Rating: 15A - 20A
  • Product Subgroup: Shop by Brand

Typical Applications

  • Motor Circuit and Motor Starter Protection
  • Control Circuit and Transformer Protection
  • HVAC and Refrigeration Equipment Circuits
  • General Purpose Branch Circuit Protection
  • Lighting Circuit Protection
  • Replacement Fuse for Fuse Blocks and Panels

Why Bussmann?

Bussmann is a well-established name in circuit protection, and the Fusetron FNM Series reflects that focus with a dual-element, time-delay design built to balance dependable overcurrent protection against nuisance opening. Selecting the correct Fusetron midget fuse for non-rejection holders helps maintain proper protection on 250-Volt AC circuits across the 15 Amp to 20 Amp range, supporting safe, code-compliant operation of the equipment it protects. For facilities and panels that already use Fusetron midget fuses, the FNM Series offers like-for-like replacements that keep overcurrent protection consistent across the electrical system.

Manufacturer Resources

Product Specs

Product Type:
Time-Delay Fuse
Series:
FNM
Voltage Rating:
250V
Configuration:
Dual-Element Time-Delay
Department:
Electrical
Product Subgroup:
Fuses
list_batch:
BUSS-20260919
Product Group:
Circuit Protection

Bussmann FNM-20 – Frequently Asked Questions

1) Will a Bussmann FNM fuse fit a standard midget fuse holder?
The FNM Fusetron is a midget-body fuse with a non-rejection ferrule configuration, so it drops into standard non-rejection midget fuse clips, holders, and blocks. If your holder is a rejection-style base (built to accept only a specific class of fuse), an FNM will not seat in it and you need the rejection-class fuse that holder was built for.
2) Can I use a 250V FNM fuse on a 480V circuit?
No. The FNM Fusetron is rated 250V AC and must not be applied above that. Using it on a 480V system is a safety problem, not just a performance one, because the fuse may not interrupt the arc. For 480V work you need a fuse rated at or above the system voltage.
3) Why does my control-circuit fuse keep blowing on motor startup, and will a time-delay fuse fix it?
That is the usual reason to move to a dual-element fuse. The FNM Fusetron pairs a fast-acting short-circuit element with a thermal time-delay element, so it rides through motor inrush and transformer magnetizing current and temporary overloads without opening, while still clearing a genuine short fast. A fast-acting midget fuse of the same amp rating on the same circuit will nuisance-trip where the FNM holds.
4) My equipment came with Fusetron midget fuses. Is the FNM a direct replacement?
For OEM equipment originally supplied with Fusetron-branded midget fuses of the same voltage class, the FNM Series is specified as a like-for-like replacement. Match the amp rating stamped on the old fuse (15 or 20 amp here) and confirm the original was 250V class.
5) What amp ratings does the Bussmann FNM Fusetron midget fuse come in?
Two ratings, 15 amp (FNM-15) and 20 amp (FNM-20), both 250V AC. Size the fuse to the circuit and load you are protecting, not to the holder.
6) What is the part number I order for a 20 amp FNM fuse?
FNM-20 is the 20 amp Bussmann Fusetron midget fuse; FNM-15 is the 15 amp. The amperage is the only thing that changes across the FNM designator, so the catalog number is simply FNM followed by the amp rating.
7) Is an FNM fuse suitable for HVAC and refrigeration control circuits in a building I manage?
Yes, that is one of its standard uses. The time-delay element handles compressor and fan motor starting current, and the 250V AC rating covers typical 120V and 208/240V control and branch circuits. Keep the same amp rating as what the equipment nameplate or panel schedule calls for, and standardizing on FNM across your panels keeps replacements consistent.
8) Should I use a dual-element time-delay midget fuse or a fast-acting one?
It depends on the load. Fast-acting midget fuses are the choice for circuits with no inrush, such as electronics, instrumentation, and semiconductor protection, where you want the quickest possible clearing. A dual-element time-delay fuse like the FNM Fusetron is for anything with a current surge at startup, motors, transformers, solenoids, and HVAC equipment, because a fast-acting fuse sized to the running current would open on every start.
How fast can I get the Bussmann FNM-20 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 Bussmann FNM-20 come with a warranty?
Absolutely. The Bussmann FNM-20 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 Bussmann FNM-20?
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
Why buy the Bussmann FNM-20 from ZenSupply?
ZenSupply makes it easy to get the commercial door hardware you need—fast shipping, expert support, and rewards on every order. Our team is always ready to help you choose the right product for your project.
!