Lights out, or the trip switch keeps going: what to check before calling an electrician

The lights have gone. Or one circuit keeps dying every time you switch something on. It is dark, and an emergency electrician at midnight is expensive.

A good share of these are two things that cost nothing to work out: a power cut, or one faulty appliance. Ten minutes of checking tells you which, and often fixes it.

1. Is it just you? Check the street

Look out of the window. Are your neighbours’ lights on? Are the street lights on?

If the whole street is dark, it is a power cut — call 105. Free, 24 hours, from any phone. It connects you straight to your local electricity network operator. It is their fault, their job and their cost, and they will have an estimated restoration time.

Do not ring an electrician for a power cut. They will charge you to tell you to ring 105.

2. Just your house? Go and look at the consumer unit

The consumer unit — the fuse box — is usually near the front door, in a hallway cupboard, under the stairs, or in a garage or basement.

Take a torch. Use the torch on your phone rather than a candle.

Look for a switch that has flipped to off or to the down position while the others are up. There are three kinds:

• The main switch — the big one. If this is off, everything is off.
• An RCD — a safety device that cuts power when it detects electricity leaking to earth. It is protecting you, and it trips fast, in milliseconds.
• An MCB — a circuit breaker for one circuit. Usually trips on overload or a short.

Note which has tripped before you touch anything. That is the diagnostic information an electrician will ask for.

3. Find the appliance that is causing it

This is the part that saves the callout, and it is a simple process of elimination.

1. Unplug everything on the affected circuit. Everything — kettle, toaster, washing machine, chargers, the extension lead behind the sofa, the outdoor socket in the garden.
2. Reset the tripped switch. Push it firmly back up.
3. If it stays up, the wiring is fine and an appliance was the cause.
4. Plug things back in one at a time, waiting a few seconds between each. The one that trips it is your culprit. Leave it unplugged. That is a job for tomorrow, not tonight.

The usual suspects: kettles, toasters, washing machines, dishwashers, immersion heaters, old extension leads, garden and outdoor sockets, and anything that has recently been rained on.

Water in an outdoor socket is the single most common cause of a mystery RCD trip, and it often appears the morning after heavy rain.

4. If it will not reset, or it trips with nothing plugged in

Now it is a wiring fault, and now you need an electrician.

But ask the honest question first: is this a tonight job or a morning job?

If you have one dead circuit, the rest of the house works, and nobody is at risk — that is a booked morning appointment at a fraction of the emergency rate. Use a lamp and an extension lead from a working circuit and go to bed.

Call tonight if the whole house is off with no power cut, if there is any sign of heat, smell or scorching, if someone in the house depends on powered medical equipment, or if you genuinely cannot make the place safe.

The legal line: what you may not do yourself

England and Wales have Part P of the Building Regulations, and it matters here.

Certain electrical work is notifiable — including installing or replacing a consumer unit. That work must either be done by an electrician registered with a government-approved competent person scheme, who can self-certify it, or be notified to local authority building control before work starts.

Practical consequences most people never hear about:

• Unnotified notifiable work can cause problems when you sell the property, because the paperwork does not exist.
• It can affect an insurance claim after an electrical fire.
• Getting it retrospectively certified is far more expensive and far more annoying than getting it right first time.

Resetting a tripped breaker is fine. Replacing a plug is fine. Anything inside the consumer unit is not yours to do.

Choosing an electrician

Electrical work has no single legal register the way gas does, so the voluntary schemes carry the weight. Look for registration with NICEIC, NAPIT, ELECSA or Stroma — schemes whose members are assessed on their work, premises, documentation and competence, and reassessed periodically.

Verify on the scheme’s own website by company name. A logo on their site is an image file.

Then the standard questions, same as every trade:

1. What is the total — callout, labour, parts and VAT?
2. Can you text me that figure before you set off?
3. Are you registered, and under which scheme?
4. Can I pay by card?

Full method: how to check any UK tradesperson in two minutes.

NICEIC publishes homeowner guidance on consumer units here.

If you rent

A dangerous electrical fault is the landlord’s responsibility, and it is urgent. Ring them or the agent first, even at 3am, and leave a timestamped message if nobody answers. Same principle as no heating or hot water and a burst pipe.

Landlords in England must also have the electrical installation inspected periodically and give tenants a copy of the report. If you have never seen one, ask for it — in writing.

The ten minutes to spend on a normal afternoon

• Find your consumer unit and know what is behind each switch. Many are labelled; if yours is not, label it.
• Test the RCD. There is a small “T” or “Test” button on it. Pressing it should trip the RCD immediately. If nothing happens, the safety device that protects your household is not working — get it looked at.
• Keep a real torch somewhere you can find in the dark. A phone torch works until the phone dies.
• Register for the Priority Services Register if anyone in the house is elderly, disabled, has a long-term health condition, is pregnant, or relies on powered medical equipment. Free, not means-tested, and it gets you priority in a power cut. Ask your energy supplier.

Sources

• NICEIC — consumer units and fuse boxes
• NAPIT
• Power cut: 105, free, 24 hours, any phone

Checked 27 August 2026. General information for England and Wales, not a substitute for a qualified electrician.