Frequently Asked Questions
What is the Littelfuse KLKR-1/2?
It is a 0.5 A Class CC fast-acting, current-limiting cartridge fuse from the Littelfuse POWR-GARD KLKR series, intended for general-purpose branch circuit protection and applications requiring fast overload response.
What is the manufacturer catalog number?
The manufacturer catalog number is KLKR.500. Littelfuse specifies the product marking KLKR 1/2 A and lists KLKR.500T as the ordering number for a manufacturer 10-piece pack.
What is the current rating of KLKR-1/2?
The current rating is 0.5 ampere, equivalent to 500 milliamperes or one-half of an ampere.
What are the AC and DC voltage ratings?
Littelfuse specifies 600 VAC and 300 VDC for the KLKR series. The circuit operating voltage must remain within the applicable AC or DC rating.
What are the interrupting ratings?
The AC interrupting rating is 200,000 amperes RMS symmetrical, and the DC interrupting rating is 20,000 amperes. Littelfuse identifies the DC rating as self-certified.
Is KLKR-1/2 fast-acting or time-delay?
KLKR-1/2 is a fast-acting fuse. It belongs to the KLKR series, which provides fast overload response. The KLDR series uses a different time-delay characteristic and is not automatically interchangeable.
Can KLKR-1/2 replace a KLDR-1/2 fuse?
Not automatically. Although both are Class CC fuses with the same nominal 0.5 A current rating, KLKR is fast-acting while KLDR is time-delay. Replacement suitability depends on circuit design, normal inrush current and required overcurrent response.
Is KLKR-1/2 suitable for solid-state electrical equipment?
Littelfuse identifies solid-state components among the applications for the KLKR series. Suitability for a particular electronic device must be verified using its protection requirements, expected operating currents and the fuse time-current characteristics.
Does Littelfuse publish a specific I²t value for KLKR-1/2?
The Littelfuse KLKR datasheet revised February 25, 2025 does not provide an individual numerical total clearing I²t value for KLKR.500 in its electrical specifications table. I²t values from other ampere ratings should not be substituted.
What are the dimensions and construction materials?
The nominal cartridge dimensions are 10.3 mm in diameter and 38.1 mm in length. The KLKR series features a melamine body and nickel-plated bronze end caps. Littelfuse specifies a series weight of 13.61 g for ratings from 0.1 A through 1 A.
Which fuse holders are recommended?
Littelfuse lists the L60030C and LPSC/LFPSC Touch-Safe holder series as accessories. Confirm Class CC compatibility and the required voltage and electrical ratings before installation.
Is KLKR-1/2 UL listed and RoHS compliant?
The KLKR series is UL Listed under file E81895 and CSA Certified under file LR29862. The manufacturer also identifies RoHS compliance and references CE Declaration of Conformity KLKR_210128_1. The DC interrupting rating is separately manufacturer self-certified.
What should be verified before ordering KLKR-1/2?
Confirm the KLKR-1/2 or KLKR.500 designation, 500 mA current rating, applicable 600 VAC or 300 VDC circuit requirement, fast-acting characteristic, interrupting capacity, Class CC fuse holder compatibility and desired purchase quantity. Littelfuse lists KLKR.500T for a manufacturer 10-piece pack; this does not establish the quantity supplied by an individual store listing.