Why does my consumer unit main breaker trip immediately when I turn it on with nothing plugged in – Advice from Electriman, North London Electricians

When your main breaker, sometimes called the main switch or incomer, trips the moment you turn it on, it is telling you there is a fault it cannot get past. The fact that nothing is plugged in and all your individual circuit breakers are off is actually an important clue. It means the fault is almost certainly not in your sockets, lights, or appliances. The problem is in the main switch itself, in the wiring between your electricity meter and the consumer unit, or in the neutral or earth connections at the very top of the board.

Here is what is safe for you to check before calling anyone.

First, make sure every individual circuit breaker inside the consumer unit is in the off position. Push them all down if you have a standard board, or move them all to off. This completely isolates your house wiring.

Second, check whether any RCDs, which are the wider switches in the middle of many boards, are also in the off position. Make sure they are.

Third, with everything else off, try the main switch once more. If it trips again instantly, do not keep trying. Repeatedly forcing a tripped breaker can cause damage or create a more dangerous situation.

Fourth, look for anything obvious. A burning smell, discolouration around the main switch, or visible damage to the cables entering the top of the board are all signs you should not touch anything further.

Fifth, check whether your neighbours have power. If they do not, the fault may

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Electriman covers Mill Hill, Barnet, Finchley, Edgware, Enfield, Watford and surrounding areas. All work is Part P certified and fully insured.