RCD tripping when plugging something into a ring main socket

2 May 2011
Reaction score
United Kingdom
Hi There
Can someone advise on the following, I have fitted a new consumer unit ie, Volex 100amp split load, with a 80amp/ 30ma RCD
With the mains switch on the consumer unit switched off, and making sure all light and socket switches throughout the house were in the 'OFF' position I carried out the following procedure in the consumer unit. I placed a tester across neutral and earth, - all clear, live and earth, - all clear, live and neutral , - all clear. I then turned on the power, and checked all sockets with a socket tester plug. All three neons lit up in the plug indicating that the wiring was correct. I then plugged in an extension lamp on each socket plug - bulb lit up with no problems. As a further test I plugged in an electric drill and directly I pressed the 'On' switch the RCD tripped out in the cu. This happened to the three 30amp ring mains, ie upstairs downstairs, and kitchen . I then used my socket tester plug again and only two neons lit up indicating a neutral fault. This happened on all three ring mains. On checking the earth the only electricity supplers earthing bond is under the floorboard and attached to the lead water pipe. I have since cross bonded the gas and water pipe with 10mm earth and run it to the cu. however the RCD keeps tripping out. As a further test, I connected the neutral wires from the downstairs ring main to the neutral bar in the cu which is not covered by the RCD - no problems at all. Finally, when pressing the 'test' button it only trips when you wiggle the actual RCD. any advice on the above would be most welcoming!
Sponsored Links
The most probable fault is you failed to tighten a terminal on the Neutral to or from the RCD. If you did not realise that was the case when you wiggled the RCD your knowledge is inadequate.

Loss of neutral is in itself not a serious risk. Loss of a neutral and defective earthing due to loose or missing connections in the earth system can make the installation extremely dangerous throughout the house.

I won't say any more, reading it will only delay you finding an electrician.
Sponsored Links
I can think of one piece.

dukeyboy - try to actually think before you leap next time.

If you knew SFA about sailing, would you think that it was OK to just jump into a boat and push off from the shore?

If you'd never ridden a motorbike would you get onto a Yamaha R1, start the engine and hope for the best?

You clearly know SFA about electrics, and yet you decided it would be OK for you to replace a CU. You should think yourself lucky that something went obviously wrong so that you'll now get someone in who knows what they are doing, and that you didn't end up with some hidden mistake waiting to kill someone.

An extremely useful life skill is to learn to pause, and ask yourself "Do I actually understand how this works and do I know what to do?", and if the answer comes back "No", to decide not to go ahead.
I hate to kick a man when he's down but the consumer unit you have installed does not sound like one that complies with wiring regulations (for domestic use)

you said
I have fitted a new consumer unit ie, Volex 100amp split load, with a 80amp/ 30ma RCD !
the neutral bar in the cu which is not covered by the RCD - !

This sounds like the old type split load with some circuits protected by an RCD and some circuits with no RCD??

Since 2008 it has been a requirement for ALL circuits to be protected by 30mA RCDS except in very specific circumstances.

You (or rather, a competent electrician) should have installed a consumer unit that has a minimum of two RCDs.

Please let us know your address so that we do not buy your house. Thanks.
Reading the description it doesn't sound like the consumer unit is configured correctly, best bet as others have said is to contact an electrician.

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links