Littelfuse JLLN Series Class T...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$14.17
Littelfuse JLLN Series Class T Fast-Acting Fuse, 300VAC

Littelfuse JLLN Series Class T Fast-Acting Fuse, 300VAC

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Model: JLLN020

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

$14.17
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Littelfuse JLLN Series Class T Fast-Acting Fuse, 300VAC

The Littelfuse JLLN Series delivers POWR-GARD Class T fast-acting fuses rated 300VAC (125VDC), available in ampere ratings from 20A to 70A to match a range of panelboard, meter stack, and equipment protection needs. Class T fuses are the most compact fuses available in ratings above 30 amperes, built in a knife-blade/bolt-in package that takes up less than one-third the panel space of comparable Class R fuses. Backed by a 200,000 A.I.R. interrupting rating shared across the JLLN family, these fuses deliver fast-acting overload and short-circuit protection for non-inductive circuits and equipment where panel space is at a premium.

Key Features

  • Ampere Rating Range: Available in 20A, 35A, and 70A fast-acting (F) Class T ratings for reliable overcurrent protection.
  • Voltage Rating: Rated 300VAC and 125VDC for use across AC and DC applications.
  • Interrupting Rating: 200,000 A.I.R. at 300VAC provides reliable interruption of overcurrents up to 200,000 amperes.
  • Package Size: Knife-Blade/Bolt-In construction fits standard Class T fuse blocks, pullouts, and switch enclosures.
  • Space-Saving Construction: Less than one-third the size of comparable Class R fuses; typical three-pole Class T fuse blocks require less than 50% of the panel area of Class R fuse blocks.
  • Extremely Current-Limiting: Stops damaging short-circuit current faster than any mechanical protective device, reducing heat and magnetic-effect damage to equipment.
  • Economical Protection: Current-limiting design often permits use of less costly downstream equipment and can prevent nuisance opening of more expensive semiconductor fuses protecting variable speed drives and rectifiers.

Certifications & Compliance

  • UL Listed (JDDZ, File E81895)
  • CSA Certified (CSA 1422-02 029862)
  • CE Marked
  • China RoHS Compliant

Technical Specifications

  • Refer to manufacturer documentation for complete technical specifications.

Typical Applications

  • Main Switches and Meter Stack Protection
  • Panelboards and Molded Case Circuit Breaker Load Centers (Series Rated)
  • Protection of Individual Electric Services and Meters
  • Input/Output Protection for Variable Speed Drives and Rectifiers
  • Commercial and Industrial Electrical Distribution Equipment

Why Littelfuse?

Littelfuse POWR-GARD Class T fuses combine an extremely current-limiting, fast-acting design with a 200,000 A.I.R. interrupting rating to deliver dependable, code-compliant overcurrent protection across the JLLN Series' 20A-70A range. Backed by UL, CSA, and CE certifications, the JLLN Series gives electrical professionals a compact, reliable choice for panelboards, meter stacks, and surge-sensitive equipment such as variable speed drives and rectifiers.

Product Specs

Series:
JLLN
Listing:
UL Listed
Product Type:
Fuse
Voltage Rating:
300VAC
Amperage Rating:
20A - 70A
Configuration:
Knife-Blade/Bolt-In
Department:
Electrical
Product Group:
Wiring Devices

Littelfuse JLLN020 – Frequently Asked Questions

1) Can I drop a Littelfuse JLLN Class T fuse into a 600V circuit?
No. The JLLN Series is rated 300VAC and 125VDC, so it can only be applied at or below those voltages. For a 480V or 600V system you need a Class T fuse in the 600V family, not a JLLN.
2) Class T or Class RK1 - which should I use for a panel that is tight on space?
Class T is the space play. The JLLN is less than one-third the size of a comparable Class R fuse, and a three-pole Class T block takes under 50 percent of the panel area a Class R block needs. Class RK1 makes more sense when you need time-delay characteristics for motor or transformer inrush, which the JLLN does not have since it is fast-acting. The Mersen A2D-R Amp-Trap 2000 is a Class RK1 time-delay option if inrush is your issue.
3) What interrupting rating do Littelfuse JLLN fuses carry, and does it cover a high available-fault service?
200,000 A.I.R. at 300VAC across the JLLN family. That covers services with available fault current up to 200kA, which is why these get used on meter stacks, main switches, and series-rated molded case breaker load centers.
4) I need a 60A fuse for a motor circuit - is the JLLN a good fit?
The Littelfuse JLLN is a fast-acting Class T fuse, which is intended for non-inductive circuits and equipment protection rather than riding through motor starting current, and its ampere range runs 20A to 70A. For a 60A motor circuit, the Mersen A2D60R is a 60A Class RK1 time-delay fuse rated 250VAC/250VDC with SmartSpot indication, and the time-delay element is the one built to tolerate inrush. Confirm the switch or block accepts R-class fuses, since Class T and Class R mountings differ.
5) What is the difference between a Littelfuse JLLN Class T fuse and a Mersen A2D-R Class RK1 fuse?
They are different fuse classes with different bodies and different response. The Littelfuse JLLN is a Class T fast-acting fuse in a knife-blade/bolt-in package rated 300VAC, offered from 20A to 70A. The Mersen A2D-R is a Class RK1 time-delay fuse rated 250VAC/250VDC with SmartSpot indication. Class T and Class R fuses are not interchangeable in the same holder, so the choice follows the block or switch already in the gear: a Class T block accepts the JLLN, and an R-rated rejection clip accepts the A2D-R. Fast-acting suits non-inductive loads and drive or rectifier circuits, while a time-delay RK1 rides through motor inrush.
6) What amp ratings does the Littelfuse JLLN Class T fuse come in?
Three ratings are offered: 20A (JLLN020), 35A (JLLN035), and 70A (JLLN070), all fast-acting Class T at 300VAC.
7) Are Littelfuse JLLN Class T fuses UL Listed for inspection sign-off?
Yes. UL Listed under JDDZ, file E81895, plus CSA certified (CSA 1422-02 029862), CE marked, and China RoHS compliant.
8) Can I use a JLLN fuse on the input of a variable speed drive?
Yes, that is one of its listed applications. The extremely current-limiting action clears short-circuit current faster than a mechanical device, which cuts the let-through heat and magnetic stress on the drive and can keep the more expensive semiconductor fuses inside the drive from opening unnecessarily. Rectifier input/output protection is the same use case.
9) I need 400A of Class T protection - does the JLLN go that high?
Not in this series. JLLN at 300VAC tops out at 70A. For a 400A fused disconnect the Mersen A2D400R is a 400A Class RK1 time-delay fuse, though note that is a different class and requires an RK1-compatible block rather than a Class T block.
10) Can I use a Square D PowerLogic meter fuse pack in place of a JLLN fuse?
No. The Square D PowerLogic Energy Meter Fuse Pack is a set of three 0.5A 600V fuses used on the metering voltage inputs of a power meter - a control-circuit sensing fuse, not a power fuse. The Littelfuse JLLN is a Class T fast-acting power fuse rated 300VAC in 20A through 70A ratings, sized for feeders, panelboards, and meter stack protection. They protect different things and share no mounting.
11) What should I use if I need more than 70 amps?
The Littelfuse JLLN Series covers 20A through 70A. Above that range, the Mersen A2D400R is a 400A Class RK1 time-delay fuse with SmartSpot indication. Note that it is a different fuse class, so it mounts in R-class blocks and clips rather than the Class T knife-blade/bolt-in mounting the JLLN uses, and it is a time-delay rather than a fast-acting element.
12) Does the JLLN have a blown-fuse indicator like the Mersen Amp-Trap 2000 fuses?
Visual blown-fuse indication is a feature of the Mersen Amp-Trap 2000 A2D-R Class RK1 line, which carries SmartSpot indication. The Littelfuse JLLN is a POWR-GARD Class T fast-acting fuse rated 300VAC with a 200,000 A.I.R. interrupting rating; it is selected for its compact knife-blade/bolt-in body, which takes less than one-third the panel space of comparable Class R fuses. If a crew wants to identify an open fuse at a glance without a meter, the indicating RK1 is the one built for that; if panel space drives the design, the Class T body is.
13) My gear is rated 250VAC - does the JLLN still work, or should I use the Mersen?
The Littelfuse JLLN carries a 300VAC rating, so it is acceptable on a 250VAC system as long as the fuse class and mounting match the block, since a fuse may be applied at or below its voltage rating. The Mersen A2D-R Class RK1 is rated 250VAC/250VDC, which matches that system voltage directly but is a time-delay fuse in a Class R body rather than a fast-acting Class T. Let the existing fuse block and the load type decide rather than the voltage number alone.
14) For a 20A branch, what is the difference between the JLLN020 and the Mersen A2D20R?
Both are 20A, and that is where the similarity ends. The Littelfuse JLLN020 is a Class T fast-acting fuse rated 300VAC in a knife-blade/bolt-in body, UL Listed. The Mersen A2D-R at 20A is a Class RK1 time-delay fuse rated 250VAC/250VDC with SmartSpot indication. The Class T body is substantially more compact, while the RK1 fits standard Class R clips and adds a delay for inrush. Match whichever class the existing holder is built to accept.
How fast can I get the Littelfuse JLLN020 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 JLLN020 come with a warranty?
Absolutely. The Littelfuse JLLN020 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 JLLN020?
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