Mersen SLR Fast-Acting Glass F...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$492.50
Mersen SLR Fast-Acting Glass Fuse, 300VAC Bayonet

Mersen SLR Fast-Acting Glass Fuse, 300VAC Bayonet

(No reviews yet) Write a Review

Model: SLR3

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

$492.50
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

Mersen SLR4 Fast-Acting Glass Fuse, 300VAC, 100-Pack

The Mersen SLR4 is a fast-acting glass cartridge fuse featuring an integral fuse and insulating cap designed for use with SHR or SHR-1 fuse holders. Rated 300VAC with a 1/2-15A ampere range and a 10kA interrupt rating, this cylindrical non-rejection style fuse is built for protection of fluorescent lighting fixtures and ballasts. Nickel plated brass contact materials and a bayonet terminal connection ensure reliable, secure engagement in compatible holders. This listing covers a 100-pack for commercial and industrial lighting maintenance and stocking needs.

Key Features

  • Ampere Range: 1/2-15 A range allows selection of the correct fast-acting protection level for a variety of fluorescent lighting and ballast circuits.
  • Fast-Acting Design: Integral fuse and insulating cap construction provides fast-acting response for use with SHR or SHR-1 fuse holders.
  • Glass Body Construction: Cylindrical non-rejection glass body allows visual inspection of the fuse element.
  • Bayonet Connection: Bayonet terminal type mounts securely into SHR-1 or SHR fuse holders.
  • Voltage & Interrupt Rating: Rated 300VAC with a 10kA AC interrupt rating for dependable circuit protection.
  • Contact Materials: Nickel plated brass contacts support consistent electrical connection and corrosion resistance.
  • Application-Specific: Engineered for protection of fluorescent lighting fixtures and ballasts.
  • Bulk Packaging: Supplied as a 100-pack for facilities and contractors maintaining lighting fuse inventory.

Certifications & Compliance

  • UL Listed/CSA Certified

Technical Specifications

  • Ac Voltage: 300 VAC
  • Ampere Range: 1/2-15 A
  • Application: Protection of fluorescent lighting fixtures and ballasts
  • Body Material: Glass
  • Body Style: Cylindrical Non Rejection
  • Ce Conformity: Consult Technical Services
  • Connection Terminal Type: Bayonet
  • I R Ac: 10kA
  • Lead Free: Consult Technical Services
  • Materials Contact: Nickel Plated Brass
  • Mounting Method: SHR-1 Or SHR
  • Rohs Compliant: Consult Technical Services
  • Standards: UL Listed/CSA Certified

Typical Applications

  • Fluorescent Lighting Fixture Protection
  • Ballast Circuit Protection
  • Commercial and Industrial Lighting Systems
  • SHR and SHR-1 Fuse Holder Installations
  • Facility Maintenance and Fuse Stocking
  • Renovation and New Construction Lighting Circuits

Why Mersen?

Mersen's SLR4 fast-acting glass fuse combines a durable cylindrical non-rejection glass body with nickel plated brass contacts and a secure bayonet connection for dependable performance in SHR and SHR-1 fuse holder systems. Backed by UL Listed/CSA Certified compliance and a 10kA interrupt rating at 300VAC, this fuse delivers consistent, code-compliant protection for fluorescent lighting and ballast circuits. Choose Mersen for reliable electrical protection products built for professional and industrial applications.

Manufacturer Resources

Product Specs

Product Group:
Wiring Devices
Materials Contact:
Nickel Plated Brass
Body Material:
Glass
Body Style:
Cylindrical Non Rejection
Lead Free:
Consult Technical Services
Standards:
UL Listed/CSA Certified
Connection Terminal Type:
Bayonet
Department:
Electrical
Ampere Range:
1/2-15 A
Product Type:
Fuse

Mersen SLR3 – Frequently Asked Questions

1) Will a Mersen SLR fuse fit an SHR-1 fuse holder?
Yes. The SLR is built specifically for SHR and SHR-1 fuse holders, and the bayonet terminal is what engages them. The fuse and insulating cap are integral, so you are not stacking a separate cap into the holder. If the holder in your fixture is not an SHR or SHR-1, the bayonet end will not seat and you need a different fuse style.
2) What amperages does the Mersen SLR glass fuse come in?
Orderable ratings are 1A, 3A, 4A, 5A, 10A and 12A, catalogued as SLR1, SLR3, SLR4, SLR5, SLR10 and SLR12. The series itself spans 1/2 to 15 A, so pick the rating that matches the ballast circuit you are protecting rather than the highest one on the shelf. Fuse amperage is not interchangeable, an oversized fuse leaves the ballast unprotected.
3) Can I use a Mersen SLR fuse on a 277V lighting circuit?
Yes, within its rating. The SLR is rated 300VAC, which covers the 277V branch circuits common in commercial fluorescent lighting as well as 120V and 240V. It carries a 10kA AC interrupting rating at that voltage. Do not put it on anything above 300VAC.
4) Is the Mersen SLR a fast-acting or a time-delay fuse, and does that matter for a ballast?
Fast-acting. It clears quickly on a fault rather than riding through an inrush, which is what fluorescent fixture and ballast protection calls for, and that is the application Mersen states for the SLR. If the load you are protecting is a motor or something else with a heavy start current, a fast-acting fuse will nuisance-open, and you want a time-delay type instead, for example the Littelfuse CCMR Series in Class CC.
5) Can I substitute a Littelfuse AGA or AGU glass fuse for a Mersen SLR?
No. The AGA and AGU are glass tube fuses with plain ferrule ends; the SLR uses a bayonet terminal and an integral insulating cap sized for SHR and SHR-1 holders. The ends are not the same, so an AGA or AGU will not mount in an SHR holder. Keep the SLR for SHR holder fixtures and use the AG-style tube fuses only where the holder takes a plain tube.
6) Is the Littelfuse AGA5 a drop-in replacement for a Mersen SLR5?
No. Both are 5A glass fuses - the Littelfuse AGA5 is an AGA Series 5A glass fuse, and Mersen offers SLR5 in its 5A amperage - but the SLR uses a bayonet connection terminal and mounts in SHR-1 or SHR fuse holders, with an integral fuse and insulating cap. A fuse that is not built to the bayonet pattern will not engage an SHR or SHR-1 holder, so match the terminal type first and the amperage second. If the holder in the fluorescent fixture is an SHR or SHR-1, the SLR family is what seats in it.
7) What fuse should I use if the circuit has inrush and a fast-acting fuse keeps opening?
Move to a time-delay fuse. The Mersen SLR is a fast-acting glass fuse in a 1/2-15 A range, which clears quickly and is intended for protection of fluorescent lighting fixtures and ballasts. Where a motor or transformer load draws a starting surge, the Littelfuse CCMR040 is a CCMR Series Class CC time-delay fuse rated 40A, built to ride through that inrush. The two are not interchangeable in the same holder - the Class CC body and the bayonet SLR body mount differently - so this is a change of both fuse and fuseholder.
8) Can I tell if an SLR fuse is blown without a meter?
Usually yes. The body is glass, so the element is visible and a ruptured link shows on inspection. It is a cylindrical non-rejection body, meaning nothing in the shape restricts it to one amp rating in the holder, so read the printed rating on the fuse before you drop a replacement in rather than assuming the one you pulled was correct.
9) I need a fast-acting fuse for a 250V circuit, not a lighting ballast. Is the SLR the right one?
Probably not. The SLR is a bayonet-terminal fuse for SHR holders in fluorescent fixtures, so it only helps you if that is the holder you have. For general-purpose fast-acting protection in a midget fuse block, the Littelfuse BLF Series is a 250V midget fast-acting fuse and a better match for standard holders.
10) Which Mersen SLR amperage do I stock for a building full of fluorescent ballasts?
Pull one of the existing fuses and match the printed rating, then stock that rating rather than mixing. Across a fleet of fixtures the ratings that come up are the six offered, 1A, 3A, 4A, 5A, 10A and 12A, and since the body is non-rejection any of them will physically seat in the same SHR holder, which is exactly why you want the right one on the shelf and not a mixed drawer. SLR4 is the common fluorescent ballast rating in the range.
11) What is the difference between the Mersen SLR and a midget fast-acting fuse like the Littelfuse BLF?
Both are fast-acting, but they are different form factors for different holders. The Littelfuse BLF is a BLF Series midget fast-acting fuse rated 250V with a laminated tube body. The Mersen SLR is a cylindrical non-rejection glass body rated 300VAC with a bayonet terminal, mounting in SHR-1 or SHR holders, and its glass body lets you see the element. Choose by the holder and the system voltage: a midget fuse block takes the BLF, an SHR or SHR-1 fixture holder takes the SLR.
12) Can I stock a Littelfuse AGU glass tube fuse instead of the Mersen SLR for fixture maintenance?
They cover different holders. The Littelfuse AGU is an AGU Series AG glass tube fuse supplied in a boxed package - a ferrule-ended glass tube that drops into clip or inline holders. The Mersen SLR is also a glass fuse but carries a bayonet terminal and an integral insulating cap so it locks into SHR or SHR-1 holders, and it comes in a 100-pack for facilities keeping lighting fuse inventory on the shelf. If the fixtures on the property use SHR-style holders, the SLR is the one that fits them; the AGU serves the clip-held circuits.
13) Which fuse goes in a metering circuit rather than a lighting fixture?
Use a fuse rated for the metering voltage. The Square D PowerLogic energy meter fuse pack is a set of three rated 0.5A at 600V, sized for meter potential leads. The Mersen SLR is rated 300VAC across a 1/2-15 A range and is engineered for protection of fluorescent lighting fixtures and ballasts, so it belongs on the fixture side, not on a 600V metering circuit. Keep the two stocked separately even though the low end of the SLR range overlaps the meter fuse amperage.
14) Will the SLR fuse contacts corrode in a damp or exterior fixture?
Contacts are nickel plated brass, which gives some corrosion resistance and holds a consistent connection in the holder clips. That is the material spec; it is not a wet-location rating for the fuse, so the fixture and holder still have to be right for the environment.
15) I need a fast-acting fuse that is UL Listed and CSA Certified for a commercial lighting circuit - what are my options?
The Mersen SLR is UL Listed and CSA Certified, fast-acting, and rated 300VAC with a 10kA AC interrupt rating, with nickel plated brass contacts. Among fast-acting alternatives, the Littelfuse BLF Series is a midget fast-acting fuse rated 250V, which is the one to look at where the panel or block takes a midget body rather than an SHR-style holder. For an institution standardizing fixture fuses across a facility, the SLR covers 1/2-15 A from a single bayonet-mount family, which keeps one holder type on the drawing.
How fast can I get the Mersen SLR3 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 SLR3 come with a warranty?
Absolutely. The Mersen SLR3 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 SLR3?
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 Mersen SLR3 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.
!