Moments later, the circuit breaker once again clicks to cut off the overload. So, you switch it back on, and off you go. Usually, ‘the cause’ can be located quite quickly: that ‘thing’ in the box on the wall is off. You’re annoyed, and you try to figure out what’s going on. The lights are out, the music is only playing in a couple of rooms or not at all, the washing machine and the dishwasher are off and the vacuum cleaner has fallen silent. Not long after, you hear a quiet ‘CLICK’ from the corner (or, in the case of older apartments, from out in the hallway). You’ve filled the dishwasher and turned it on, the washing machine is full of clothes and you’ve flicked the switch, you’ve pulled the vacuum cleaner out of its corner and plugged it in. In preparation, you’ve compiled your favorite MP3 playlist on your PC and it’s being streamed in all rooms. You’ve just decided to get your annual spring clean over and done within record time tonight. Just imagine you live in an apartment built maybe sometime in the 60s. However, if someone then asks what miniature circuit breakers, or MCBs, actually do, my answer might go a little something like this: When people ask me “What do you actually do?” I say “I work for ABB and am responsible for miniature circuit-breakers within product marketing.” Then, I either get perplexed expressions or a friendly “oh, right…” as an answer. Everyone knows what it is-but not everyone knows what it does.

Abb circuit breaker instruction book