When a Circuit Breaker Trips It Is Doing Its Job

This is less a set of instructions about a tripping circuit breaker than an argument, and it is worth saying so at the start.

Two kinds of protection

One type of device protects against too much current flowing in a circuit, whether from overload or from a short circuit. Another type detects current leaking to earth, which is the situation that causes electric shock, and disconnects extremely quickly.

The names for these differ between countries, and the function is the same wherever you are. A trip is therefore information: something has drawn too much current, or current has found a path it should not have. Treating a trip as an inconvenience to be reset is the mistake, because the device operated for a reason that still exists.

Finding what caused it

Unplug everything on the affected circuit, and switch off the lights on it if that is the circuit involved. Reset the tripped device, and if it holds, plug items back in one at a time with a pause between each. The item that causes it to trip again is the fault, and that appliance should be taken out of use rather than used carefully.

Faulty kettles, toasters, heaters and anything with a heating element are the most common domestic culprits. A trip that happens at a particular moment, such as when a fridge motor starts or a shower is switched on, points directly at that appliance.

When to stop and call someone

If the device will not reset with everything unplugged, the fault is in the fixed installation and needs a qualified electrician. If it trips again immediately after resetting, do not keep trying, since repeated resetting into a fault is genuinely dangerous. Any burning smell, scorch mark, warm socket or discoloured faceplate means stop using that circuit and get it inspected.

By the second month, buzzing, crackling or a socket that sparks when something is plugged in are all faults rather than quirks. Water near electrical fittings, or a trip that coincides with a leak, is an emergency rather than a maintenance issue.

The things you must never do

Never replace a protective device with one of a higher rating, since the rating is matched to the cable it protects. Never wedge, tape or otherwise hold a device in the on position, which removes the protection entirely. Never open the sealed section of the consumer unit or attempt work on fixed wiring, which is regulated in most countries.

Never assume an old rewireable fuse can be repaired with any available wire, since the fuse rating is a safety specification.

These are not cautious recommendations, they are the situations that cause house fires and fatal shocks.

Reducing nuisance trips

Earth leakage devices can trip from the cumulative small leakage of many appliances rather than from one fault. Older appliances, outdoor equipment and anything that has been damp are the common contributors.

Spreading high-demand appliances across circuits and across time reduces overload trips, which are a demand problem rather than a fault. Extension leads running several high-power items from one socket are a frequent and avoidable cause. If nuisance tripping persists after removing obvious causes, an electrician can test the installation and identify where the leakage is.

Leave gas, mains electrics and anything behind a wall to someone qualified and insured.

Renting and periodic inspection

In rented property the electrical installation is the landlord's responsibility, and many countries now require periodic inspection and certification. Ask for the current electrical safety certificate at the start of a tenancy, since providing it is a legal duty in a growing number of jurisdictions. Report any electrical fault in writing immediately, and stop using the affected circuit while waiting.

Do not arrange your own electrician for the fixed installation without agreement, since the landlord is responsible for the work and the certification. Appliances you own are yours, and an appliance causing repeated trips should be replaced rather than nursed along.

The takeaway

Unplug, reset once, reintroduce one at a time, and if it still trips it belongs to an electrician.

A home that works is a set of small systems, not one big clean.