Cooper Bussmann JKS-40 Class J Fast-acting Fuse 40A 600V

Product Description

The COOPER BUSSMANN JKS-40 is a Class J fast-acting cartridge fuse rated at 40 amps and 600 volts, with an interrupting rating of 200 kiloamps (RMS). Designed for general-purpose overcurrent protection, it delivers fast response to fault currents, helping protect downstream components from damage. The cartridge body measures 2.375 inches in length and 27 mm in diameter, sized to fit standard Class J fuse holders. Electricians and industrial maintenance technicians install this fuse in disconnect switches, motor control panels, and distribution equipment where Class J dimensions and high interrupting capacity are required.

This fuse is suited for residential, commercial, and light industrial electrical systems that demand Class J overcurrent protection. Typical applications include branch circuit protection, motor branch circuits, and equipment panels where fast-acting response characteristics are specified. Its 600-volt rating covers a wide range of single-phase and three-phase systems commonly found in commercial and light industrial facilities.

Key Features

• 40-amp rating with fast-acting response for rapid fault clearing
• 600-volt AC rating suitable for single-phase and three-phase systems
• 200 kA RMS interrupting rating for high fault-current environments
• Class J cartridge body fits standard Class J fuse holders
• CE Certified, CSA C22.2 No. 248.8 Class J, and UL Listed 248-8 Class J (Guide JDDZ, File E4273)

Compatibility

Designed for use in Class J fuse holders and disconnect switches sized for the Class J form factor at 40 amps and 600 volts.

Installation Notes

Installation should be performed by a licensed electrician in accordance with the National Electrical Code (NEC) and any applicable local codes. De-energize and lock out the circuit before replacing or inspecting any fuse. Verify that the fuse holder is rated for Class J fuses and that the circuit voltage and amperage do not exceed the fuse ratings. Never install a fuse with a higher amperage rating than the circuit is designed to carry.