How to find what is tripping my circuit breaker

Here’s everything you need to know about what a circuit breaker is, what causes a circuit breaker to trip and why yours keeps on doing it…

What is a circuit breaker?

An electrical circuit breaker is a mechanical device which is designed to detect and interrupt faulty current on an electrical circuit.

The one which everyone will be familiar with is the circuit breaker box in your own home. This box will interrupt the power in your property if anything is abnormal. This protects the circuit from damage and you from electrocuting yourself.

How does a circuit breaker work?

Let’s take a quick step back and think about how electricity works for a moment. Electricity is defined by three different values:

• Voltage – can be thought of as the pressure which makes an electric charge move;
• Current– is the rate at which the charge moves.
• Resistance– comes from the material which the electric charge is moving through and will resist this flow.

These three values are all linked like this: Current = voltage / resistance

Okay, we’ve got that. Now onto the circuit breaker:

A circuit breaker essentially consists of rows of contacts. When everything is working normally – when the power grid is feeding your house electricity at a consistent voltage, all of the lights and appliances in your home are providing a certain level of resistance and the current stays within safe limits – then these contacts are closed together by the pressure of a spring. Current flows across the contacts and your home has power.

When something goes wrong, however, the circuit breaker has a special “trip coil” which becomes energised by excess current and forces the contacts apart. The power will go out. But you are safe.

What causes a circuit breaker to trip?

When a circuit breaker trips to shut off the electrical flow, it does so for a reason. In the UK, there are usually one of three causes:

1) Overloaded circuit

An overloaded circuit will normally be the reason your circuit breaker keeps tripping.

The culprit is usually the combination of lights and appliances you have on the same circuit. It could also be a faulty appliance which is calling for more current than it usually requires.

Here’s how to find out if this is your problem:

• Have you noticed any appliances which are making a lot of noise, generating a lot of heat or seeming to work less efficiently than normal?
• Have you recently started running a new appliance of any kind? Or perhaps recently plugged in one you only run during certain seasons, such as a storage heater?
• Did turning on a specific appliance or device cause the breaker to trip?

If you unplug the offending device and the power works normally, you have found your problem.

Here’s what to do about it:

If this is the problem, you’re either going to need to:

• Turn off some of the appliances or devices hooked up to the circuit. You won’t be able to use them all at the same time.
• Speak to an electrician about installing a new dedicated circuit or increasing the load the existing circuit can take.

2) Short circuit

There are several types of wires running through your home. Active or “hot” wires are the ones which carry the current. If they ever come into contact with each other – or with neutral wires – this will result in more current than the circuit can handle, causing the breaker to trip.

This is known as a short circuit.

Here’s how to find if this is your problem:

• Have you noticed if your electric keeps tripping while accompanied by a burning smell or, in the worst case, smoke?
• Have you spotted any sparks or crackling noises?
• Can you see blackening around any of your electrical sockets?

Here’s what to do about it:

If this is the problem, you need to:

• Leave the circuit breaker tripped – do not try and switch it back on.
• Call an emergency electrician immediately.

The fix might be a relatively simple one when it comes down to it. But short circuits are a serious fire hazard. You don’t want to be messing around with them.

3) Ground faults and what to do about them

Ground faults are very similar to short circuits. But instead of an active wire coming into contact with a neutral wire, it is coming into contact with a grounding wire.

The symptoms of a constantly tripping circuit breaker caused by a ground fault are the same as those listed above for a short circuit. Watch out for burning smells and discoloured sockets in particular.

If anything though, a ground fault is even more dangerous. That’s because they ruin the safety function of your grounding wire.

Again, if you suspect this is the kind of fault that’s causing the problem, you need to leave the circuit breaker in the OFF position and call your emergency electrician right away.