Littelfuse KTN-R-4 Fast-Acting Fuse Class RK1

KTN-R-4 is a Littelfuse KLNR-series UL Class RK1 fast-acting fuse rated 4 A at 250 V (AC) and 250 V (DC). This current-limiting device is designed for general-purpose protection in power and control circuits, opening quickly to interrupt faults and minimize damage to equipment. It carries an interrupting rating of 200 kA RMS at 250 VAC, making it suitable for use in RK1 fuse blocks and standard panel protection where fast overcurrent response is required. The 1‑fuse package aligns with the KTN-R‑4 designation used in Bussmann/Eaton catalogs and is commonly cross-referenced for replacement in equipment that originally employed KTN-R devices, fitting standard RK1 form-factor holders in panels and enclosures.