Littelfuse IDSR Series Class R...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$14.06
Littelfuse IDSR Series Class RK5 Dual-Element Indicating Time-Delay Fuse, 600V

Littelfuse IDSR Series Class RK5 Dual-Element Indicating Time-Delay Fuse, 600V

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Model: IDSR015

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

$14.06
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Littelfuse IDSR Series Class RK5 Dual-Element Indicating Time-Delay Fuse, 600V

The Littelfuse IDSR Series is the IDSR Indicator™ line, the first indicating power fuse ever built, using a solid-state design for state-of-the-art circuit protection. This Class RK5 dual-element time-delay fuse is rated 600VAC/600VDC and is available in ampere ratings from 15A to 200A (15A, 30A, 60A, 200A), each with a built-in indicator window that shows at a glance whether the fuse has opened. Maintenance staff can identify a faulted circuit and request the correct replacement without wasting time testing fuses one by one, reducing unplanned downtime. Housed in an industrial cartridge package, the IDSR Series is built for demanding commercial and industrial power distribution.

Key Features

  • Ampere Rating Range: available in 15A, 30A, 60A, and 200A ratings to match a wide range of industrial cartridge fuse applications.
  • Visual Open-Fuse Indication: a glance at the window confirms if the fuse has opened, if the window is dark, the fuse has blown, so no fuse testing is required to pinpoint the faulted circuit.
  • Dual-Element Time-Delay Design: Slo-Blo/Time Lag (T)/Time Delay opening characteristic in a patented Class RK5 fuse construction.
  • Electrical Rating: 600VAC and 600VDC voltage rating with a 20000A@600VDC interrupting rating for demanding circuits.
  • Superior Time Delay: Littelfuse-patented leading-edge metallurgy eliminates moving parts, overriding current surges without sacrificing protection against sustained overloads.
  • Patented Fuse Design: the first totally new dual-element time-delay Class RK5 fuse design in 10 years, surpassing the performance of the original Littelfuse SLO-BLO® fuse introduced in 1984.
  • Package Size: Industrial Cartridge fuse body across the IDSR Series.
  • Reduced Down-Time: operators can immediately identify an open fuse and request the correct replacement from maintenance personnel, cutting troubleshooting time and preventing system damage.

Certifications & Compliance

  • UL JDDZ E81895
  • CSA 1422-02 029862

Technical Specifications

  • Refer to manufacturer documentation for complete technical specifications.

Typical Applications

  • Solenoids
  • Transformers
  • Fluorescent Lighting
  • Motors
  • System Components with High Inrush Currents
  • General-Purpose Circuits

Why Littelfuse?

Littelfuse engineered the IDSR Indicator™ Series with patented dual-element Class RK5 construction and leading-edge metallurgy to deliver reliable, code-compliant circuit protection across the 15A-200A range for critical power distribution. Backed by UL and CSA recognition, the IDSR Series gives maintenance teams a faster, more dependable way to spot an open fuse, reduce unnecessary testing, and get equipment back online with confidence.

Product Specs

Series:
IDSR
Product Type:
Fuse
Voltage Rating:
600VAC/600VDC
Configuration:
Dual-Element Time-Delay
Listing:
UL Listed
Standards:
CSA
Department:
Electrical
Product Group:
Wiring Devices

Littelfuse IDSR015 – Frequently Asked Questions

1) What amp ratings does the Littelfuse IDSR Class RK5 fuse come in?
The IDSR Indicator series is offered in four ratings: 15A (IDSR015), 30A (IDSR030), 60A (IDSR060) and 200A (IDSR200). All four share the same 600VAC/600VDC rating and the same dual-element time-delay characteristic, so you can standardize a panel across the range and only the amp rating changes on the order.
2) Can I use the IDSR fuse on a 240V or 480V circuit, or is it strictly 600V?
600V is the maximum. A fuse rated 600VAC/600VDC can be applied at any system voltage at or below that, so 208V, 240V and 480V distribution are all within rating. What you cannot do is go the other way and put a 250V-rated fuse into a 600V holder. That is one thing to watch if you are cross-shopping the Mersen A2D-R, which is listed at 250VAC/250VDC.
3) How does the indicator window on the Littelfuse IDSR fuse tell you a fuse has blown?
Each IDSR carries a built-in indicator window driven by a solid-state design. If the window is dark, the fuse has opened. That lets an operator point maintenance straight at the faulted circuit and name the replacement rating instead of pulling and ohming every fuse in the block, which is where most of the troubleshooting time goes on a motor or lighting panel.
4) Will a Class RK5 time-delay fuse hold on motor and transformer inrush?
That is exactly what the dual-element time-delay construction is for. The IDSR rides through the inrush surge of motors, transformers, solenoids and fluorescent lighting while still opening on a sustained overload. Littelfuse uses a patented metallurgy with no moving parts to get that delay. For general-purpose circuits with no inrush, a non-time-delay fuse would also work, but the time-delay version lets you size closer to running current on inductive loads.
5) Is the Littelfuse IDSR fuse UL listed and CSA approved?
Both. The IDSR is UL Listed under JDDZ E81895 and carries CSA 1422-02 029862. For a facility spec that calls out UL-recognized Class RK5 overcurrent protection with CSA acceptance for Canadian sites, that pairing covers it.
6) Will a Class RK5 fuse fit my existing Class R fuse block or rejection clips?
Class RK5 and Class RK1 share the same physical case dimensions and the same rejection feature for a given amp rating and voltage, so an RK5 drops into a Class R rejection block. What changes between them is the let-through energy: RK1 clears faster and lets through less, so if your equipment label or drawing calls specifically for Class RK1, substitute a true RK1 such as the Mersen A2D-R rather than an RK5.
7) What is the closest alternative to the Littelfuse IDSR if I need an indicating time-delay fuse above 200A?
The Littelfuse IDSR Series dual-element time-delay fuse is offered in 15A, 30A, 60A and 200A ratings. For a higher-amperage indicating time-delay fuse, the Mersen A2D400R is a Class RK1 400A time-delay fuse with SmartSpot indication. Note the class difference: the IDSR is Class RK5 construction while the A2D400R is Class RK1, so confirm the fuseblock and the overcurrent protection called out on the drawing before swapping.
8) Is the Mersen A2D-R a direct substitute for a Littelfuse IDSR fuse?
Not directly. The Littelfuse IDSR is a Class RK5 dual-element time-delay fuse rated 600VAC/600VDC with a visual open-fuse indicator window. The Mersen A2D-R is a Class RK1 time-delay fuse with SmartSpot indication, and the A2D-20R version is rated 250VAC/250VDC. Both give you visible blown-fuse indication, but RK1 has different let-through characteristics than RK5 and the 250V A2D-20R cannot be used where a 600V fuse is specified.
9) What is the interrupting rating on the Littelfuse IDSR fuse?
The IDSR is rated 20,000A at 600VDC. If your available fault current at the panel exceeds that on the DC side, this is not the right fuse for the location and you need a higher interrupting device.
10) I need more than 200A of Class R protection. Is there an option?
The IDSR line tops out at 200A with IDSR200. Above that, step to a larger Class R fuse from another line, for example the Mersen A2D400R, a 400A Class RK1 time-delay fuse with SmartSpot indication. Keep in mind that changing class from RK5 to RK1 changes let-through characteristics, and the block must be sized for the larger case.
11) Is the Littelfuse IDSR a cartridge fuse or a plug/ferrule style?
Industrial cartridge body across the whole IDSR range. It is not a medium-voltage ferrule fuse, so if your application is a medium voltage E-rated ferrule holder you want something like the Mersen D0R0 Series Amp-Trap instead.
12) Can I use the Square D EMFP3 fuse pack in place of a Littelfuse IDSR fuse?
No. The Square D PowerLogic EMFP3 is a set of three 0.5A 600V fuses for metering circuits, sized to protect the voltage inputs of an energy meter. The Littelfuse IDSR Series is a Class RK5 dual-element time-delay branch and feeder fuse in 15A through 200A ratings for motors, transformers, solenoids and other high-inrush loads. They share a 600V rating and nothing else about the application.
13) The IDSR is a low-voltage cartridge fuse. What do I use on a medium voltage circuit instead?
The Littelfuse IDSR Series is an industrial cartridge fuse rated 600VAC/600VDC, so it is not applicable above that class. For medium voltage, the Mersen A055F1D0R0-150E is an Amp-Trap E-rated medium voltage fuse with ferrule terminals from the D0R0 series. Confirm the E rating and mounting against your switch or transformer primary before ordering.
How fast can I get the Littelfuse IDSR015 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 Littelfuse IDSR015 come with a warranty?
Absolutely. The Littelfuse IDSR015 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 Littelfuse IDSR015?
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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