Cooper Bussmann JJN-20 Class T Fast-acting Fuse 20A

Product Description

The COOPER BUSSMANN JJN-20 is a Class T fast-acting cartridge fuse rated at 20 amps, designed for general-purpose overcurrent protection in industrial and commercial electrical systems. It carries an interrupting rating of 200 kA at AC (RMS) and 20 kA at DC, making it suitable for high-fault-current environments where rapid response to overloads and short circuits is required. The cartridge body measures 10.3 mm in diameter and 22.2 mm in overall length (approximately 7/8 inch long). Licensed electricians and electrical maintenance technicians are the primary installers of Class T fuses in panelboards, disconnect switches, and control equipment.

The JJN-20 is suited for use in residential, commercial, and light industrial electrical distribution applications where Class T fuse holders are specified. Its compact cartridge form factor fits standard Class T fuse blocks and disconnect enclosures. The fast-acting response characteristic makes it appropriate for protecting branch circuits and equipment where time-delay characteristics are not required and immediate interruption upon fault is the priority.

Key Features

• 20-amp continuous current rating for general-purpose branch circuit protection
• 200 kA interrupting rating at AC (RMS) for high-fault-current installations
• 20 kA interrupting rating at DC
• Compact cartridge body: 10.3 mm diameter, 22.2 mm overall length
• Fast-acting fuse timing for immediate fault interruption
• CE Certified, CSA Certified (C22.2 No. 248.15), and UL Listed (248-15 Class T)

Compatibility

Designed as an OEM-style replacement for Class T fuse holders and disconnect switches that accept cartridge fuses with a 10.3 mm diameter body profile.

Installation Notes

Installation should be performed by a licensed electrician in accordance with the National Electrical Code (NEC) and applicable local codes. Always de-energize and lockout/tagout the circuit before removing or installing fuses. Use an appropriately rated fuse puller for cartridge fuse removal. Verify that the fuse holder is rated for Class T fuses and matches the voltage and amperage requirements of the circuit before installation.