If your power keeps cutting out, the cause is usually one of a few common issues. Some are easy to fix yourself. Others need a qualified electrician. This guide helps you work out which.

First: identify what is cutting out

Before you can diagnose the problem, you need to understand exactly what is happening:

A single circuit goes off (e.g. just the kitchen sockets, or just the upstairs lights). Look at your consumer unit. One of the switches will be in the “down” or “off” position.
Half the house goes off. This usually means an RCD has tripped, cutting power to all circuits protected by that RCD.
Everything goes off. The main switch has tripped, or there is a problem with the incoming supply.

The pattern tells you where to look.

Single circuit cutting out

Overloaded circuit

If an MCB trips, it may simply be that you are drawing more current than the circuit is rated for. This is common in kitchens where a kettle (13A), a toaster (5A), and a microwave (5A) are all on the same ring circuit at the same time.

What to try: Reduce the load by unplugging some appliances. If the tripping stops, the circuit is overloaded but not faulty.

Faulty appliance

A specific appliance may be causing the trip. This is the most common cause.

What to try: Unplug everything on the affected circuit, reset the breaker, then plug appliances back in one at a time. The one that causes the trip is the faulty appliance.

Damaged cable

If the tripping is intermittent and not linked to a specific appliance, a damaged cable within the circuit may be the cause. This can happen after DIY work (drilling into a cable), rodent damage, or cable degradation in older properties.

What to do: Call an electrician for a fault finding inspection.

Half the house cutting out

RCD tripping

If an RCD trips, it cuts power to all circuits connected to it. On a typical split-load consumer unit, this means roughly half your circuits go off at once.

The RCD has detected a current imbalance, which means current is leaking to earth somewhere. This could be:

A faulty appliance
Water ingress to a socket or junction box
Damaged cable insulation
A fault developing in an outdoor circuit (especially after rain)

What to try: Switch off all MCBs under the tripped RCD, then reset the RCD. Turn the MCBs back on one at a time. The circuit that causes the RCD to trip again is the one with the fault.

If your consumer unit has RCBOs (individual combined devices for each circuit), this problem is less disruptive because only the affected circuit trips, not half the house. A consumer unit upgrade to RCBOs resolves this.

Everything cutting out

Main switch tripping

If the main switch on your consumer unit trips, there may be a serious fault within the installation, or the main switch itself may be faulty.

What to do: Do not repeatedly reset it. Call an electrician.

Supply issue

If the main switch has not tripped but you still have no power, the issue may be with the incoming supply:

Check if your neighbours are also affected. If they are, the problem is with the electricity network.
Check your prepayment meter (if you have one). It may have run out of credit.
Check the supply fuse (the sealed unit before your consumer unit). If this has blown, contact your electricity distributor (the company that owns the cables, not your energy supplier).

Intermittent total power loss

If your entire supply drops out intermittently (lights dim or flicker, appliances reset), this may indicate a loose connection on the incoming supply, a failing main switch, or a neutral fault. These are all serious issues. Contact an electrician.

When to call an electrician

Call an electrician if:

You cannot identify the cause after basic checks
The same circuit trips repeatedly
The RCD trips and you cannot isolate which circuit is causing it
The main switch trips
You notice any burning smell, scorch marks, or warmth at the consumer unit
The power cuts are intermittent with no obvious pattern
You suspect damaged wiring

Keeping a record

If your power has been cutting out intermittently, note down:

The date and time it happens
Which circuits are affected
What appliances were in use at the time
The weather conditions (rain can trigger outdoor circuit faults)

This information helps an electrician diagnose the issue more efficiently.

Next steps

If your power keeps cutting out and you cannot find the cause, contact us for a fault finding appointment. We carry out systematic testing to locate the fault and fix it.

Related services:

Need help with this? Get a free, no-obligation quote.

Get in touch

Power Keeps Cutting Out: Common Causes