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How to find the cause of a tripping RCD

How to find the cause of a tripping RCD.

So your RCD has suddenly tripped now none of your socket outlets are working.
This quick how to should enable you to quickly find the fault, follow the below steps sequentially for a quick solution.
This guide assumes that you have power to your premises and only deals with socket circuit faults.
If you still have lighting in your premises but none of your sockets are working follow the guide below, otherwise there are more serious issues involved and it is not recommended that you attempt to carry out any further exploratory work except for ensuring that the surrounding electricity customers are also without power. If this is not the case contact your local registered electrical contractor immediately and they shall advise.

1: Locate your CU (Consumer Unit, commonly reffered to as a fuse board) this will usually be located in a utility room near the back door of your premises or inside the front door of your premises.

2: Determine the MCBs (Miniature Circuit Breakers) which are associated with your socket circuits, these will usually have a marking of B20. The CU should also be legibly marked clearly indicating which MCBs are for sockets.

3: Switch off all the MCBs which are controlling the socket circuits.

4: Reset your RCD, this should be clearly marked on your CU and with most new RCDs also has a blue coloured switching mechanism and test button.
If at this point the RCD immediately trips you should double check that all the socket circuit breakers are in the off position. Note the off position is when the MCB is in the down state this is the opposite to your standard light switch.

5: If point (4) fails above you should proceed by plugging out all devices plugged into each socket outlet as there could well be an Neutral to Earth Fault in some device. You can then reset the RCD and start plugging back in devices until the RCD again trips. If the RCD trips will all devices plugged out then the issue may be more serious and we recommend that contact your local registered electrical contractor for further assistance.

6: With your RCD reset you should proceed to enable the socket MCBs one by one, At the point where you find the RCD trips after enabling a certain MCB stop the procedure.

7: Now disable the MCB that caused the RCD to trip and enable all the other MCBs, finally reset your RCD.

8: If your RCD stays solid then you have successfully diagnosed the faulty socket circuit.

9: To find the faulty appliance which is causing the RCD to trip you must now disconnect all items which are plugged in to this circuit.

10: Once you have unplugged all appliances that on the faulty circuit you must then re-enable the MCB which initially tripped the RCD.
If at this point the RCD trips double check that all appliances have been unplugged and repeat from step (7).

11: If the RCD continues to trip you should contact your local registered electrical contractor as there must be an issue with the hardwiring or outlets.

12: If your RCD stays on after unplugging all devices then the next thing to do is plug them in one by one until you find the appliance that trips the RCD,
At this point you have now successfully identified the faulty appliance.

13: Leave this item unplugged and plug back in all other items then reset your RCD.

14: All that’s left to do is get this item checked out by a professional or return it if under warranty, a likely source of the problem would be a kettle or toaster.