BUSSMANN DFJ-40 NSNBC01 Fuse

DFJ-40 is a Bussmann (Eaton) Class J high-speed drive fuse rated for 40 A and 600 VAC (450 VDC). Encased in a cylindrical body, the device measures about 1.060 inches in diameter and 2.380 inches long (approximately 26.92 mm × 60.45 mm), with a typical 27 × 60 mm footprint. It is designed for fast protection in motor drives, servo drives, power supplies, and other industrial equipment where quick interruption is required without excessive nuisance tripping. The fuse cartridge requires a compatible holder and is listed for UL Class J and CSA recognition. The 40 A DFJ-40 variant provides fast-acting protection against overcurrent at up to 600 VAC, and in data sheets it is associated with an I2t value of about 90 A²·s at 600 VAC (pre-arc 100 kA), illustrating its balance of rapid clearing with manageable energy let-through. This makes it well suited for drive circuits and other high-inrush environments where maintaining continuous operation is essential while still safeguarding downstream components. Available through major distributors such as DigiKey, Mouser, Grainger, and National Fuse, the DFJ-40 sits within the Bussmann DFJ family of Class J fuses, offering compact, standards-based protection that aligns with typical drive-system protection schemes.