How to Fit a Wylex and Crabtree Starbreaker Miniature Circuit Breakers (MCB) into a Consumer Unit EAL Awards City & Guilds Students training aid on how to fit miniature circuit breakers into distribution boards (fuse board, consumer unit or a fuse box). This videos shows you the advantages of using Crabtree Starbreaker range over the Wylex consumer units that have a bus bar for the circuit breaker to sit on. I demonstrate how to fit a conventional circuit breaker MCB to the din rail and then fit