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Lost Power at Home? Here’s What to Do If Your RCD Has Tripped

Updated: Jun 16

I've lost half the power to the house—can anyone recommend an electrician?”


Sound familiar? You're not alone. This is one of the most common electrical issues we get asked about, and the cause is often something simple: a tripped RCD.


This guide will help you understand what an RCD is, how to reset it safely, how to find the cause of the fault, and when it's time to call in a professional.


Why did I lose power in part of my house?


If only part of your home has lost power — like all the sockets or just the lights — it’s likely that an RCD in your fuse board has tripped. This happens when a fault or imbalance is detected on one of the circuits.


What is an RCD?


An RCD (Residual Current Device) monitors the balance between live and neutral wires. In a healthy circuit, the current flowing in and out is equal.

If a fault develops — like water getting into a socket or a faulty appliance — the current leaks to earth, causing an imbalance. The RCD detects this and trips off to prevent electric shock or fire.


How to Tell If Your RCD Has Tripped


Open your consumer unit (fuse board). A dual RCD board will usually have two RCDs, each protecting a group of circuits, with 8–10 MCBs (Miniature Circuit Breakers) beside them.

Look for a switch that’s in the down or off position — that’s likely your RCD.



Dual rcd consumer unit
Hager dual RCD consumer unit with labels


Some boards use RCBOs instead, which combine RCD and MCB protection in a single device. Want to know the difference between dual RCD boards and RCBOs? Read our full comparison guide here.



Rcbo consumer unit
Hager RCBO consumer unit with labels

How to Reset Your Fuse Board Safely

  1. Switch the RCD fully down to OFF.

  2. Turn off all MCBs (the smaller switches beside it).

  3. Now, turn the RCD back ON.

  4. One by one, turn each MCB back ON, leaving a few seconds between each.

  5. When you reach the faulty circuit, the RCD will trip again.

  6. Turn that circuit OFF and leave it off.

  7. Reset the RCD and turn the remaining circuits back on.

The majority of your power should now be restored.


General MCB Ratings – What Each Circuit Might Be For


  • 50/45/40 amp will be for cookers, hobs, electric showers or a sub main feed to home offices, sheds, summer houses

  • 32 amp will be for sockets around your home or a sub main feed to a garage or shed, but can also be for cookers, hobs or hot tubs.

  • 20 amp or 16 amp will be for just a few sockets around your home or possibly a feed to a garage, water heaters or electric fires.

  • 10 amp or 6 amp will be for lighting.


How to Check for a Faulty Appliance


This is one of the most common causes of RCD tripping. A faulty appliance on a socket circuit (usually 16A, 20A or 32A) could be the culprit.

Here’s how to test:

  1. Unplug all appliances from the affected circuit — don’t just turn off the socket switches.

  2. Reset the RCD. If it stays on, the fault was likely one of those appliances.

  3. Plug each item back in one at a time. When the RCD trips again, you’ve found the faulty item.

Common offenders: Kettles, irons, dishwashers, fridges, freezers.Fridge faults can be tricky — they may only trip when the motor kicks in. An appliance engineer can confirm.


How to Test for a Faulty Light Fitting

If the issue is with your lighting:

  1. With the lighting MCB switched OFF, go around the property and switch all light switches to the opposite position.

  2. Reset the RCD.

  3. Now switch lights back on one at a time. If the RCD trips when a certain light is turned on, that fitting is likely faulty.


Common Causes of Intermittent Tripping

If your RCD trips sporadically with no clear cause, here are a few likely reasons:

Water ingress

Maybe the outside lights have failed, the outside socket is letting water in, leaking water pipes, or there are roof issues

Damaged cables

cables screwed through/pinched, DIY gone wrong.

Rodent damage

Vermin chewed through the insulation of the cables in the loft, walls, or under suspended floors

Loose connections

Incorrectly terminated wiring accessories or junction boxes

Thermal/Fire damage

Incorrectly installed cables or accessories.

These kinds of sporadic faults are often referred to as nuisance tripping, and RCBO consumer units are designed to help prevent this by isolating each circuit individually.


In some cases, a full Electrical Installation Condition Report (EICR) is the best way to get to the bottom of recurring faults or tripping issues.



What to Tell the Electrician


If you do need to call us out, here’s how to help us help you quickly — and potentially save time (and money):

  • When did the power go off?

  • What were you doing at the time?

  • Which appliances were on?

  • Has anyone done DIY recently?

  • Have you noticed a loose socket or light switch?

  • Any new carpets or floorboards been screwed down?

  • Heard mice in the walls or loft?

  • Was it raining heavily?

The more info you can give us — even if it seems unimportant — the faster we can find the fault and get you back up and running.


Need Help?

With over 20 years of experience, Eclipse Electrical Kenilworth is trusted by local homeowners to identify faults quickly, restore power safely, and provide long-term solutions.



📞 Call us on 01926 354690




Or call us on 01926 354690

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