Consumer unit - Definition and Overview

Wylex standard consumer unit fitted with rewirable fuses

A consumer unit is a box of fuses or breakers usually arranged in a single row. This can be contrasted with a distribution board which has multiple rows of fuses or breakers and usually serves two (which may be split phase, two phase or two phases taken from three phase) or three phases.

A consumer unit fitted with just fuses is often referred to as a fuse box.

Modern consumer units usually use DIN-rail mount breakers.

The box pictured is a "Wylex standard". This type was very popular in the British Isles up until very recently when the wiring regulations started demanding RCDs for sockets that could feasibly supply equipment outside the equipotential zone. The design does not allow for fitment of RCDs or RCBOs (a RCBO is the combination of a RCD and a MCB in a single unit). The one pictured is fitted with rewirable fuses but they can also be fitted with cartridge fuses and MCBs (miniature circuit breakers).