Littelfuse BLF Series Midget F...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$5.57
Littelfuse BLF Series Midget Fast-Acting Fuse, 250V, Laminated Tube

Littelfuse BLF Series Midget Fast-Acting Fuse, 250V, Laminated Tube

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Model: BLF009

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

$5.57
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Littelfuse BLF Series Midget Fast-Acting Fuse, 250V, Laminated Tube

The Littelfuse BLF Series is a midget fast-acting fuse line rated 250VAC, purpose-built for control circuit and instrument protection in dry locations. Housed in an economical laminated tube construction, the BLF Series is engineered as the lowest-price midget fuse in the Littelfuse lineup, giving panel builders and OEMs an affordable way to protect low-current control and instrumentation circuits without sacrificing performance. Available in 0.5A and 9A ampere ratings, the BLF Series combines a Fast-Acting (F) opening characteristic with a 10,000A interrupting rating at 250VAC to respond quickly to overcurrent conditions and help protect downstream components and wiring. Its compact Midget/5AG package size allows it to drop into standard midget fuse blocks and holders commonly found in control panels, instrumentation racks, and industrial equipment.

Key Features

  • Ampere Rating Options: Available in 0.5A and 9A ratings, allowing precise overcurrent protection sized to the control circuit or instrument being protected.
  • Voltage Rating: Rated 250VAC across the series, suitable for control circuit and instrument protection applications operating at standard control voltages.
  • Fast-Acting Response: Fast-Acting (F) opening characteristic delivers quick circuit interruption under fault conditions, helping limit damage to downstream equipment.
  • Interrupting Rating: 10,000A interrupting rating at 250VAC ensures reliable performance and safe clearing under high fault-current conditions.
  • Compact Midget Package: Midget/5AG package size fits standard midget fuse holders and blocks in space-constrained control panels and instrument enclosures.
  • Economical Laminated Tube Design: Laminated tube construction makes the BLF Series the lowest-price midget fuse option from Littelfuse, reducing per-point protection cost across large installations.
  • Dry Location Use: Suitable for control circuit and instrument protection in dry locations, matching typical indoor panel and instrumentation environments.

Technical Specifications

  • Series: BLF

Typical Applications

  • Control Circuit Protection
  • Instrument and Panel Meter Protection
  • Industrial Control Panels
  • OEM Equipment and Machinery Protection
  • Dry-Location Panel and Enclosure Installations
  • Midget Fuse Block and Holder Replacement

Why Littelfuse?

Littelfuse engineers the BLF Series with laminated tube construction to deliver reliable, fast-acting overcurrent protection at an economical price point, making it a practical choice when many protection points are needed across a control system. With 250VAC ratings, a 10,000A interrupting capacity, and ampere options spanning 0.5A to 9A, the BLF Series is built to clear faults safely across a range of control circuit and instrument protection applications. For professionals specifying dependable, cost-effective fuse protection for dry-location control panels and instrumentation, Littelfuse offers the BLF Series as a trusted, purpose-built solution.

Product Specs

Series:
BLF
Voltage Rating:
250VAC
Product Type:
Fast-Acting Fuse
Amperage Rating:
0.5A - 9A
Department:
Electrical
Product Group:
Circuit Protection
Product Subgroup:
Fuses

Littelfuse BLF009 – Frequently Asked Questions

1) Will a Littelfuse BLF fuse fit a standard midget fuse holder?
Yes. The BLF Series uses the Midget/5AG package, so it drops into standard midget fuse blocks and holders found in control panels and instrumentation racks. If your existing holder takes midget fuses, the BLF is a direct physical fit.
2) Can I use a BLF fuse on a 480V control circuit?
No. The BLF Series is rated 250VAC only. For circuits above that voltage you need a fuse rated for the system voltage, for example the Square D PowerLogic meter fuse pack rated 0.5A 600V.
3) Is the BLF fuse interrupting rating high enough for an industrial panel?
It clears 10,000A at 250VAC. That covers typical control and instrumentation branches fed through a transformer. If your available fault current at that point exceeds 10kA, you need a higher interrupting-rating fuse instead.
4) Fast-acting or time-delay fuse for a control circuit with a transformer or motor starter?
The BLF is fast-acting (F), so it opens quickly on overcurrent and protects downstream wiring and instruments. That is the wrong choice where inrush is present, such as a control transformer or starter coil, because the fuse will nuisance-open. For those loads use a time-delay type like the Mersen A2D-R Class RK1 time-delay fuse.
5) What is the difference between the Littelfuse BLF midget fuse and a Mersen A2K Class RK1 fuse at the same 250V rating?
Both are fast-acting 250V fuses, but they are different physical classes and are not interchangeable in a holder. The Littelfuse BLF Series is a midget (5AG) package fast-acting fuse rated 250VAC with a 10,000A interrupting rating, sized for standard midget fuse blocks in control panels. The Mersen A2K Series is a fast-acting Class RK1 fuse at 250V, which uses the larger Class R body with rejection features and mounts in Class R fuse clips or blocks. Use the BLF where the panel is built around midget holders for control and instrument circuits, and the A2K where the drawing calls out Class RK1 branch or feeder protection.
6) My panel drawing calls for a time-delay fuse, not fast-acting. What should I use instead of the BLF?
The Littelfuse BLF Series is a fast-acting (F) fuse and will not ride through motor or transformer inrush. For a time-delay characteristic, the Mersen A2D-R is a Class RK1 time-delay fuse with SmartSpot indication, which also gives a visual blown-fuse indicator. Note the A2D-R is a Class R body rather than a midget package, so the fuse block or clips have to suit Class R dimensions.
7) Is the 0.5A BLF fuse the same thing as the fuses in the Square D PowerLogic energy meter fuse pack?
They share an ampere rating but not a voltage class. The Littelfuse BLF.500 is a 0.5A midget fast-acting fuse rated 250VAC. The Square D PowerLogic Energy Meter Fuse Pack is a set of three 0.5A fuses rated 600V, supplied as a kit for metering circuits. If a PowerLogic meter installation specifies the 600V rating, the 250VAC BLF is not the right substitute; if you are protecting a 250V control or instrument circuit in a midget holder, the BLF.500 is the one sized for that.
8) What amp ratings does the Littelfuse BLF midget fuse come in?
Two ratings are offered: 0.5A (BLF.500) and 9A (BLF009). The series range is published as 0.5A to 9A, so size the fuse to the control circuit or instrument you are protecting rather than to the holder.
9) Can BLF fuses be installed in a wet or outdoor enclosure?
No. The laminated tube construction limits the BLF Series to dry locations, which means indoor panels, instrument enclosures and machine control cabinets. For damp or outdoor service, specify a fuse built for that environment.
10) What part number do I order for a 0.5 amp BLF fuse?
The 0.5A rating is Littelfuse part BLF.500; the 9 amp is BLF009. Both are BLF Series, 250VAC midget fuses.
11) I need a fast-acting fuse above 9A for a feeder, not a control circuit. What is the alternative to the BLF Series?
The Littelfuse BLF Series covers 0.5A to 9A and is intended for control circuit and instrument protection, so it tops out below typical feeder duty. For higher-current fast-acting protection, Mersen offers the A2K12R in the A6K-R Series as a Class RK1 fast-acting fuse, which uses a Class R body and rejection-style mounting instead of a midget holder. Confirm the amp rating and class called out on the one-line before ordering.
12) Can a Mersen Amp-Trap E-rated fuse be used in place of the Littelfuse BLF in a control panel?
No. The Littelfuse BLF Series is a 250VAC midget fuse for low-current control and instrument circuits in dry locations. The Mersen A055F1D0R0-150E is an Amp-Trap E-rated medium voltage fuse with ferrule terminals, built for medium voltage transformer and feeder protection on an entirely different system class. The two are not alternatives to each other at any amp rating.
13) Why pick the BLF over another Littelfuse midget fuse?
Cost per protection point. The laminated tube body makes BLF the lowest-price midget fuse in the Littelfuse line, which matters when an OEM panel has dozens of fused control and metering points. The tradeoff is that it is dry-location, fast-acting, 250VAC only.
How fast can I get the Littelfuse BLF009 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 BLF009 come with a warranty?
Absolutely. The Littelfuse BLF009 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 BLF009?
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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