Bussmann FNQ-4 Fuse

The FNQ-4 fuse from Bussmann (Eaton Bussmann series) is a 4 A, 500 VAC time-delay (slow-blow) midget cartridge fuse designed for industrial protection of panels and power circuits. Its compact form measures 10.3 mm by 38.1 mm (13/32 in x 1-1/2 in) and it uses a cartridge-style fuse element that drops into a matching FNQ fuse holder. The device is non-indicating, providing no built-in blown-status window, which is typical for FNQ fuses. It is intended where brief inrush currents occur—such as motor starters, drives, and power-supply protections—allowing these surges to pass without nuisance blowing while still protecting the circuit from sustained overcurrent. The FNQ-4 is RoHS compliant, aligning with modern environmental and safety standards, and it is part of the Bussmann FNQ family of time-delay fuses used widely in industrial equipment and control panels. To install, pair it with a compatible Bussmann FNQ fuse holder and the assembly will fit in standard panel-board or equipment enclosures that require 500 VAC-rated protection.