Littelfuse FLQ Series 500V Slo...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$28.14
Littelfuse FLQ Series 500V Slo-Blo Midget Fuse

Littelfuse FLQ Series 500V Slo-Blo Midget Fuse

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Model: FLQ.250

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

$28.14
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Littelfuse FLQ Series 500V Slo-Blo Midget Fuse

The Littelfuse FLQ Series 500V Slo-Blo Midget Fuse is a time-delay fuse line built to deliver dependable supplemental circuit protection wherever high inrush currents are present, and this product page covers both the FLQ.250 and FLQ.600 models. Every FLQ Series fuse carries UL and CSA 500-volt ratings for use on 480-volt circuits, is built in the compact Midget/5AG package size for standard fuse holders and fuse blocks, and is rated 500VAC / 300VDC with a 10000A@500VAC interrupting rating. The Slo-Blo/Time Lag (T) opening characteristic protects control power transformers, solenoids, and small motors from damaging overcurrent conditions without nuisance tripping during normal startup surges.

Key Features

  • Voltage Rating: Rated 500VAC and 300VDC, FLQ Series fuses carry UL and CSA 500-volt ratings that permit use on 480-volt circuits for broad application flexibility.
  • Time-Delay Operation: The Slo-Blo/Time Lag (T) opening characteristic provides excellent supplemental protection for control power transformers, solenoids, and circuits subject to high inrush currents.
  • Interrupting Rating: A 10000A@500VAC interrupting rating gives these fuses the capacity to safely clear high fault currents in demanding electrical systems.
  • Package Size: Built in the compact Midget/5AG package size, FLQ Series fuses fit standard midget fuse holders and fuse blocks used throughout industrial and commercial equipment.
  • Model Options: Available in FLQ.250 and FLQ.600 versions to match different amperage requirements within the same Slo-Blo Midget platform.
  • Motor Protection: FLQ fuses also provide supplemental protection to small motors, guarding connected equipment against sustained overcurrent conditions.
  • Branch-Circuit Guidance: For motor branch-circuit protection applications, Littelfuse recommends its Class CC fuse line rather than the FLQ Series.

Certifications & Compliance

  • UL Listed for circuit protection applications
  • CSA Certified for use in Canadian electrical systems
  • 500-Volt Rating Permits Use on 480-Volt Circuits

Technical Specifications

  • Series: FLQ
  • Amperage Rating: 0.250A (FLQ.250)
  • Standards: UL-CSA

Typical Applications

  • Control Power Transformer Protection
  • Solenoid Circuit Protection
  • High-Inrush Current Circuits
  • Supplemental Protection for Small Motors
  • Industrial and Commercial Control Panels

Why Littelfuse?

Littelfuse engineers the FLQ Series to meet UL and CSA 500-volt standards, giving electrical professionals a fuse line they can rely on for consistent, code-compliant performance across both FLQ.250 and FLQ.600 models. The Slo-Blo time-delay design and 10000A@500VAC interrupting rating reflect the kind of robust construction demanded in commercial and industrial control circuits. Choose the Littelfuse FLQ Series for supplemental protection built to keep control power transformers, solenoids, and small motors running safely.

Product Specs

Product Type:
Time-Delay Fuse
Series:
FLQ
Amperage Rating:
0.250A
Voltage Rating:
500VAC
Standards:
UL-CSA
Department:
Electrical
Product Group:
Circuit Protection
Product Subgroup:
Fuses

Littelfuse FLQ.250 – Frequently Asked Questions

1) Can I use a Littelfuse FLQ midget fuse on a 480V control circuit?
Yes. The FLQ Series carries UL and CSA 500-volt ratings, and that 500V rating is what permits use on 480-volt circuits. Full rating is 500VAC / 300VDC, with a 10,000A interrupting rating at 500VAC, so it will clear high fault currents on an industrial control panel feed.
2) Will a Littelfuse FLQ fuse fit a standard midget fuse holder or fuse block?
It will. FLQ fuses are built in the Midget/5AG package size, which is what standard midget holders and midget fuse blocks used in industrial and commercial equipment are made to take. No adapter or special block needed.
3) Can I use FLQ fuses for motor branch-circuit protection?
No. FLQ is a supplemental protection fuse. It will protect a small motor against sustained overcurrent, but for motor branch-circuit protection Littelfuse directs you to its Class CC fuse line instead. If your drawing calls out branch-circuit protection, FLQ is the wrong part.
4) Which amperage ratings does the Littelfuse FLQ Slo-Blo midget fuse come in?
Two very low ratings: 1/4 amp (FLQ.250) and 6/10 amp (FLQ.600). Both are the same 500V Slo-Blo midget platform, so the only decision is the amp draw of the control transformer primary or solenoid circuit you are protecting. Order by the exact model number, since the two look alike in a holder.
5) What is the difference between the Littelfuse FLQ Series midget fuse and the Mersen A2D-R Class RK1 time-delay fuse?
Both are time-delay fuses, but they are built for different jobs. The FLQ Series is a Slo-Blo midget (5AG) fuse rated 500VAC / 300VDC and intended for supplemental protection of control power transformers, solenoids, and small motors; Littelfuse directs motor branch-circuit protection to its Class CC line instead. The Mersen A2D-R is an Amp-Trap 2000 Class RK1 time-delay fuse with SmartSpot indication, a full branch-circuit and feeder class in the larger Class RK1 body. If your drawing calls for a Class RK1 fuse in a disconnect, the FLQ will not fit that holder or satisfy that callout.
6) I need a fuse for a medium voltage transformer circuit - is the Littelfuse FLQ the right choice?
No. The FLQ Series tops out at 500VAC / 300VDC and is a low-voltage supplemental protection fuse. For medium voltage transformer duty the comparable part is the Mersen A055F1D0R0-150E, a D0R0 Series Amp-Trap E-rated medium voltage fuse with ferrule terminals, which is the construction and rating class used for medium voltage transformer protection.
7) Why use a Slo-Blo fuse instead of a fast-acting one on a control transformer?
A control power transformer, solenoid, or small motor draws a large inrush spike at energize. A fast-acting fuse sees that spike as a fault and opens. The FLQ uses a Slo-Blo / Time Lag (T) characteristic that rides through the startup surge and still opens on a sustained overcurrent, which is why it is specified on high-inrush circuits. If your load has no inrush and you want the fastest clearing, a fast-acting type such as the Mersen A2K Series Class RK1 is the other direction to look.
8) Is the Littelfuse FLQ fuse UL Listed and CSA certified?
Both. The FLQ Series is UL Listed for circuit protection and CSA Certified for Canadian installations, carried under a UL-CSA standards designation. That matters on panel builds that have to pass inspection on either side of the border.
9) Is the Square D PowerLogic energy meter fuse pack an alternative to the Littelfuse FLQ for metering circuits?
They serve different purposes. The Square D PowerLogic EMFP3 is a meter fuse pack supplied as a set of three, rated 0.5A at 600V, matched to PowerLogic energy meter voltage inputs. The Littelfuse FLQ Series is a single Slo-Blo midget fuse rated 500VAC / 300VDC, sold in 1/4A and 6/10A amperages, for control power transformers, solenoids, and small motors. If you are fusing a PowerLogic meter, order the meter fuse pack; if you are protecting a control circuit in a panel, the FLQ is the midget-format part.
10) What should I use instead of the FLQ if I need a fast-acting fuse at a higher amperage for a feeder?
The Littelfuse FLQ Series is a Slo-Blo time-delay midget fuse in low amperages such as 1/4A and 6/10A, so it is not a feeder device. For a fast-acting fuse in a Class RK1 body, the Mersen A2K12R in the A6K-R Series is the fast-acting Class RK1 part in the comparable lineup, and the Mersen A2K Series fast-acting Class RK1 fuse is rated 250V. Confirm which voltage class your disconnect requires before ordering.
11) Can I use a 500V FLQ fuse on a 240V or 120V control circuit?
Yes. A fuse voltage rating is a maximum, so the 500VAC-rated FLQ is fine on lower-voltage control circuits such as 240V or 120V secondaries. What you cannot do is go the other way and use a lower-voltage fuse on a 480V circuit.
12) Which of these fuses gives a visual indication that it has opened?
Of the comparable time-delay options, the Mersen A2D-R Class RK1 fuse is supplied with SmartSpot indication, which gives a visual cue at the fuse. The Littelfuse FLQ Series is a Slo-Blo midget fuse without an indicating feature in its description, so panels using FLQ fuses are typically troubleshot with a meter or an indicating fuse holder.
How fast can I get the Littelfuse FLQ.250 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 FLQ.250 come with a warranty?
Absolutely. The Littelfuse FLQ.250 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 FLQ.250?
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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