Bussmann LIMITRON KTN-R Series...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$229.50
Bussmann LIMITRON KTN-R Series Class RK1 Fast-Acting Fuse

Bussmann LIMITRON KTN-R Series Class RK1 Fast-Acting Fuse

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Model: KTN-R-40

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

$229.50
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Bussmann LIMITRON KTN-R Series Class RK1 Fast-Acting Fuse

The Bussmann LIMITRON KTN-R Series is a family of Class RK1 fast-acting fuses engineered for reliable overcurrent protection in panelboards and other electrical distribution equipment. This series is available in amperage ratings from 40A to 50A, with every fuse in the family rated 250V and built to the same construction standard for consistent, dependable performance. Each LIMITRON KTN-R fuse features a melamine glass tube body fitted with 70/30 brass end caps for durable, conductive construction, and is supplied with ferrule end x ferrule end terminals for straightforward mounting into standard fuse clips and holders. All fuses in this family are built as non-indicating fuse bodies, meaning they do not include a blown-fuse indicator. As part of the Bussmann LIMITRON KTN-R family, these fuses are designed to deliver fast-acting response for Class RK1 rated applications, providing dependable circuit protection wherever LIMITRON KTN-R type fuses are specified. Select the amperage rating that matches your panelboard or equipment requirements from the 40A-50A range offered in this series.

Key Features

  • Amperage Rating Range: Available from 40A to 50A to suit a range of panelboard branch circuit protection needs.
  • Voltage Rating: 250V rated across the series for use on compatible electrical distribution systems.
  • Class RK1 Fast-Acting Design: Part of the Bussmann LIMITRON series, providing fast-acting overcurrent response.
  • LIMITRON KTN-R Series: Manufactured as part of the Bussmann LIMITRON KTN-R fuse family.
  • Ferrule End x Ferrule End Terminals: Ferrule-style terminals on both ends for compatibility with standard fuse clips and holders.
  • Melamine Glass Tube Construction: Durable melamine glass tube body supports consistent fuse performance across the series.
  • 70/30 Brass End Caps: Brass end caps provide a secure, conductive connection at each terminal.
  • Non-Indicating: Standard non-indicating fuse body without a blown-fuse indicator, common to every rating in this series.
  • Panelboard-Rated: Sized and rated for use in panelboards requiring Class RK1 protection.

Technical Specifications

  • Amperage Rating: 40A - 50A (select at checkout)
  • Product Weight: .9 pounds
  • Product Height: 3 inches

Typical Applications

  • Panelboard Circuit Protection
  • Branch Circuit Overcurrent Protection
  • Commercial and Industrial Electrical Distribution Equipment
  • Replacement Fuse for LIMITRON KTN-R Series Applications
  • General Purpose Overcurrent Protection for Electrical Equipment
  • Equipment and Electrical Panel Protection

Why Bussmann?

Bussmann fuses in the LIMITRON KTN-R series are built with durable materials, including melamine glass tube bodies and 70/30 brass end caps, to deliver consistent, dependable overcurrent protection across the full 40A-50A range. This Class RK1 fast-acting series reflects the LIMITRON line's reputation for reliable performance in panelboard and electrical distribution applications. Ferrule end x ferrule end terminals make every fuse in this family straightforward to install into compatible fuse clips and holders for professional electrical work.

Manufacturer Resources

Product Specs

Product Type:
Fast-Acting Fuse
Series:
LIMITRON KTN-R
Voltage Rating:
250V
Connection Type:
Ferrule End x Ferrule End
Configuration:
Ferrule End x Ferrule End
Department:
Electrical
Product Subgroup:
Fuses
list_batch:
BUSS-20260919
Product Material:
Melamine Glass
Class:
Class RK1
Product Weight:
.9 pounds
Product Height:
3 inches
End Type:
Ferrule
Product Finish:
Brass End Caps
Product Group:
Circuit Protection
Product Length:
0.81 in
Product Width:
0.81 in

Bussmann KTN-R-40 – Frequently Asked Questions

1) Can a Bussmann KTN-R fuse be used on a 480V circuit?
No. The LIMITRON KTN-R is a 250V fuse, so it is limited to circuits of 250 volts or less. For 600V service you need the 600V counterpart of the Class RK1 line, the KTS-R, not the KTN-R. Installing a 250V fuse on a 480V system is a misapplication no matter what the amp rating is.
2) Will a ferrule-end KTN-R drop into my existing Class R fuse clips?
Yes, within reason. Both the 40A and 50A KTN-R are built ferrule end x ferrule end, which is the standard Class R form at these ratings, so they seat in standard 250V Class R fuse clips and fuse holders without adapters. Class R holders also carry a rejection feature, so a Class R fuse like this one fits a Class R block while a plain Class H one-time fuse will not.
3) Is a fast-acting RK1 fuse right for a motor circuit, or do I need time-delay?
The KTN-R is fast-acting, so it clears overcurrents quickly and suits feeders, panelboard branch circuits, and non-inductive equipment loads. On a motor or transformer with high inrush, a fast-acting fuse can open on starting current; for those loads you want the dual-element time-delay Class RK1 fuse (Bussmann FRN-R at 250V) instead. Same Class R mounting, different time-current behavior.
4) What amp ratings does the LIMITRON KTN-R fast-acting fuse come in?
Two ratings are offered, 40A (KTN-R-40) and 50A (KTN-R-50), both 250V. Pick the one that matches the branch circuit or equipment nameplate you are protecting. The two are physically the same ferrule-end body, so the only thing you are choosing is the ampere rating.
5) Can I swap a KTN-R for a Class RK5 fuse of the same amperage?
Physically yes, since both are 250V Class R ferrule fuses that fit the same rejection clips, but they are not equivalent protection. RK1 like the KTN-R is the higher interrupting, lower let-through class; RK5 lets more energy through. If the panel schedule or equipment label calls for Class RK1, fit RK1. Going the other way, from RK5 to RK1, keeps the amp rating and raises the protection level.
6) I need to restock spare fuses for several panels. Which part numbers do I order?
For the 250V Class RK1 fast-acting LIMITRON line in this range, order KTN-R-40 for 40 amp positions and KTN-R-50 for 50 amp positions. Both share the same ferrule-end construction, so one fuse puller and one holder style covers both. Match the ampere rating to the panel schedule for each circuit rather than stocking one size for everything.
7) How will I know a KTN-R has blown?
You will not know by looking at the end cap. Every rating in the LIMITRON KTN-R family is a non-indicating body with no blown-fuse indicator, so troubleshooting means pulling the fuse and testing continuity, or metering across it. If your maintenance crew relies on visual indication, plan for a fuse puller and a meter at the panel rather than expecting a pop-out pin.
8) What is the KTN-R fuse made of and how big is it?
The body is a melamine glass tube with 70/30 brass end caps, and the stated height is 3 inches. Melamine glass holds up to the thermal cycling you get in a working panel, and the brass caps give a solid conductive seat in the clips. Shipping weight is listed at .9 pounds.
How fast can I get the Bussmann KTN-R-40 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 KTN-R-40 come with a warranty?
Absolutely. The Bussmann KTN-R-40 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 KTN-R-40?
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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