Littelfuse FLSR_ID Series Clas...
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Littelfuse FLSR_ID Series Class RK5 Dual-Element Fuse with Blown-Fuse Indicator, 600V

Littelfuse FLSR_ID Series Class RK5 Dual-Element Fuse with Blown-Fuse Indicator, 600V

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Model: FLSR005ID

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

$14.01
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Littelfuse FLSR_ID Series Class RK5 Dual-Element Fuse with Blown-Fuse Indicator, 600V

The Littelfuse FLSR_ID Series is a Class RK5 dual-element, time-delay indicator fuse family available in ratings from 0.2A to 70A, rated 600VAC and 300VDC for broad application flexibility across AC and DC circuits. Built on a patented, solid-state design with true dual-element construction, this Industrial Cartridge fuse delivers a 20,000A@300VDC interrupting rating and Slo-Blo/Time Lag (T) time-delay opening characteristics for demanding industrial and commercial power circuits. A built-in indicating window shows an open fuse at a glance, with power on or off, helping reduce troubleshooting time and unnecessary exposure to live parts.

Key Features

  • Amp Rating Range: Available from 0.2A to 70A across the FLSR_ID Series for accurate, dependable overcurrent protection sized to the application.
  • Voltage Rating: 600VAC and 300VDC for broad application flexibility across AC and DC circuits.
  • Interrupting Rating: 20,000A@300VDC delivers robust short-circuit protection for demanding installations.
  • Opening Characteristic: Slo-Blo/Time Lag (T) time-delay design lengthens fuse life and reduces nuisance opening.
  • Package Size: Industrial Cartridge configuration for standard fuse holders and switches.
  • Visual Blown-Fuse Indicator: a patented solid-state indicating window shows an open fuse at a glance, with power on or off, so no fuse testing is required.
  • True Dual-Element Design: improves safety and reliability while helping reduce downtime and equipment damage from overload and short-circuit events.
  • Reduced Live-Circuit Exposure: built-in indication works whether the circuit is energized or de-energized, minimizing the need to work near live parts just to check fuse condition.

Certifications & Compliance

  • UL Recognized Component (JDDZ E81895)
  • CSA Certified (1422-02 029862)

Technical Specifications

  • Refer to manufacturer documentation for complete technical specifications.

Typical Applications

  • Switchboard Main and Feeder Switches
  • Service Entrance Switches
  • Industrial Control Panels
  • Motor Control Center Mains and Motor Branch Circuits
  • Distribution Panelboards
  • Protection of Fully-Rated Panelboards and Loadcenters

Why Littelfuse?

Littelfuse FLSR_ID Series fuses pair true dual-element, solid-state construction with UL Recognized and CSA Certified compliance for dependable, code-compliant overcurrent protection across the full 0.2A to 70A rating range. The built-in indicating window lets electrical professionals spot an open fuse instantly, helping reduce troubleshooting time, downtime, and exposure to live circuits, while superior overload and short-circuit performance helps protect equipment across industrial control panels, switchboards, motor control centers, and distribution equipment.

Product Specs

Product Type:
Fuse
Series:
FLSR_ID
Voltage Rating:
600VAC / 300VDC
Amperage Rating:
0.2A - 70A
Standards:
UL-CSA
Department:
Electrical
Product Group:
Wiring Devices

Littelfuse FLSR005ID – Frequently Asked Questions

1) Will a Class RK5 fuse drop into my existing Class R fuse block or disconnect?
Yes, provided the block is a Class R rejection type sized for the same amp range and voltage. The FLSR_ID is an industrial cartridge package built to Class R dimensions, so it fits standard Class R holders and fused switches. Note the rejection feature works one way: a Class R block also accepts Class RK1 fuses, but a non-rejection block that took an old Class H or K fuse should not be back-filled without confirming it is rated for the job.
2) Should I specify Class RK5 or Class RK1 for my panel?
RK5 like the Littelfuse FLSR_ID is the general-purpose dual-element time-delay choice for feeders, service entrance switches, control panels and motor circuits. RK1 is the current-limiting-tighter option when the equipment short-circuit rating or the let-through energy on the drawing calls for it; in that case a Mersen A2D-R Class RK1 time-delay fuse with SmartSpot indication is the equivalent with a visual indicator, and the A2D400R covers a 400A frame that the FLSR_ID range does not reach. Both classes share Class R rejection mounting.
3) What is the difference between the Littelfuse FLSR_ID fuse and the Mersen A2D-R with SmartSpot indication?
Both are time-delay cartridge fuses with a visual blown-fuse indicator, but they sit in different UL fuse classes. The Littelfuse FLSR_ID is a Class RK5 dual-element time-delay fuse rated 600VAC and 300VDC, with a patented solid-state indicating window that shows an open fuse whether the circuit is energized or not. The Mersen A2D-R is a Class RK1 time-delay fuse using SmartSpot indication. RK1 and RK5 share the same rejection-style dimensions and will fit the same Class R holders and switches, so the choice comes down to the let-through performance your equipment or panel schedule calls out. If the drawing specifies Class RK1, order the A2D-R; if it specifies RK5, the FLSR_ID is the match.
4) I need a time-delay fuse above 70 amps - what should I use instead of the Littelfuse FLSR_ID?
The FLSR_ID family tops out at 70A, with ratings running from 0.2A to 70A. For a larger feeder or main, the Mersen A2D400R is a 400A Class RK1 time-delay fuse with SmartSpot indication, which covers the higher end of the Class R range while keeping the time-delay characteristic and a visual blown-fuse indicator. Confirm the class your panel or switch is prepped for before ordering, since RK1 and RK5 are specified differently on many drawings.
5) What amp ratings does the Littelfuse FLSR_ID series come in?
The series spans 0.2A to 70A. Stocked ratings include 0.2A, 1.25A, 2.5A, 2.8A, 3.5A, 4.5A, 5A, 8A, 12A, 20A, 30A, 40A, 50A and 70A, ordered as FLSR200ID through FLSR070ID (for example FLSR030ID is the 30 amp).
6) I need more than 70A of Class R protection. What do I use?
The FLSR_ID family stops at 70A. For larger frames, step to a Class RK1 line such as the Mersen A2D-R series, which includes a 400A A2D400R with SmartSpot indication. Check that your switch or block is rated for the higher amperage before ordering.
7) Are Littelfuse FLSR_ID fuses UL and CSA approved for a commercial panel?
They are UL Recognized Components under JDDZ, file E81895, and CSA Certified under 1422-02 029862. The Standards field on the product reads UL-CSA.
8) Can the FLSR_ID be used on a DC circuit?
Yes, up to 300VDC, with a 20,000A interrupting rating at that voltage. That covers common DC control and battery-backed circuits. Do not apply it above 300 volts DC even though the AC rating is 600 volts.
9) Which FLSR_ID part number do I order for a small control transformer circuit under 5 amps?
The low end of the series is well populated for control work: 0.2A (FLSR200ID), 1.25A (FLSR1.25ID), 2.5A (FLSR025ID), 2.8A (FLSR02.8ID), 3.5A (FLSR035ID) and 4.5A (FLSR045ID). The time-delay element handles transformer inrush. If you only need a small fixed set for metering, the Square D PowerLogic Energy Meter Fuse Pack ships as a set of three 0.5A 600V fuses.
10) Is the Mersen D0R0 Amp-Trap fuse an alternative to the Littelfuse FLSR_ID?
No. The Mersen D0R0 Series Amp-Trap is an E-rated medium voltage fuse with a ferrule terminal, intended for medium voltage transformer and feeder protection. The Littelfuse FLSR_ID is a 600VAC / 300VDC Class RK5 industrial cartridge fuse for low voltage work such as switchboard mains, industrial control panels, motor control centers and distribution panelboards. The two are not interchangeable in either direction - the holder, the voltage class and the application are all different.
11) For metering circuits, should I order a Littelfuse FLSR_ID or the Square D PowerLogic fuse pack?
Use the Square D PowerLogic Energy Meter Fuse Pack for PowerLogic meter voltage inputs - it is a set of three 0.5A 600V fuses sold specifically for that duty. The Littelfuse FLSR_ID is a Class RK5 dual-element time-delay fuse sized for power circuits and branch protection, with its smallest rating at 0.2A and a range up to 70A, and it carries a blown-fuse indicating window for field troubleshooting. If the meter manufacturer specifies its own fuse pack, follow that; the FLSR_ID is the choice for the feeder or branch circuit feeding the equipment.
12) Which time-delay fuse gives me a blown-fuse indication I can read without pulling the fuse?
Both the Littelfuse FLSR_ID and the Mersen A2D-R offer that. The FLSR_ID uses a patented solid-state indicating window that shows an open fuse at a glance with power on or off, so no fuse testing is needed and there is less reason to work near live parts. The Mersen A2D-R uses SmartSpot indication on a Class RK1 time-delay body. The practical difference for ordering is class: FLSR_ID is Class RK5 covering 0.2A to 70A, while the A2D-R line is Class RK1 and includes ratings up to 400A in the A2D400R.
How fast can I get the Littelfuse FLSR005ID 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 FLSR005ID come with a warranty?
Absolutely. The Littelfuse FLSR005ID 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 FLSR005ID?
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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