Cooper Bussmann MDQ-1/2 Cartridge Time Delay Fuse 0.5A

Product Description

The COOPER BUSSMANN MDQ-1/2 is a mini cartridge time delay fuse rated at 0.5 amps. It features a glass body construction with dual elements and is designed to provide time-lag overcurrent protection in low-amperage control circuits. The time delay characteristic allows momentary inrush currents to pass without nuisance blowing, then interrupts sustained overloads before damage occurs. At 1.25 inches overall length and 0.25 inches in diameter, this fuse fits standard mini cartridge fuse holders used across HVAC control boards, small appliances, and electronic equipment. Installation is performed by qualified electricians and HVAC technicians working on low-voltage or signal-level circuits.

This fuse is suited for residential and light commercial applications where precise overcurrent protection at low amperages is required. Common install scenarios include HVAC control circuit protection, transformer secondary circuits, and electronic equipment panels. The 0.5 amp rating targets sensitive components that would be damaged by even moderate overcurrent events. The time delay design distinguishes it from fast-acting fuses where motor or transformer inrush currents would cause repeated failures.

Key Features

• Time delay (slow-blow) characteristic prevents nuisance blowing on inrush currents
• Glass cartridge body allows visual inspection of fuse element condition
• Dual-element design for reliable time-delay response
• Compact mini form factor: 1.25 inches OAL x 0.25 inches diameter
• UL Listed under UL 248-14 and CSA Class 1422-01 Component Accepted

Compatibility

Designed as an OEM-style replacement mini cartridge time delay fuse for use in standard 1/4 inch diameter mini cartridge fuse holders in HVAC control circuits, electronic equipment panels, and similar low-amperage overcurrent protection applications.

Installation Notes

This fuse should be installed by a licensed electrician or qualified HVAC technician. De-energize the circuit completely and verify zero voltage before removing or inserting the fuse. Always replace with a fuse of identical amperage rating and time delay classification — substituting a fast-acting or higher-rated fuse defeats the protection intent. Reference NEC Article 240 for general overcurrent device installation requirements.