rcd keeps tripping nothing plugged in - please help!

[Alexander Robinson]

Hi All,


On Saturday night about 1am (give or take a couple of hours) our RCD tripped, if we turn the socket breaker off then the main RCD will stay on, (lights kitchen etc) Our kitchen units are on a separate breaker so it won’t be the fridge/freezer.

We have unplugged all appliances taken out all the fuses from spurs (To our knowledge) and it still trips when nothing is plugged in,

Before we get an electicrian to rip open the walls to check cabling does anyone know anything else we could do? Any help is greatly appreciated.


Alex

 

[omega015]

With ALL the MCB's on the RCD side switched off, reset the RCD to the ON position. It stays on, correct? If so, switch on 1 MCB at a time until you find the MCB that trips the RCD. Which circuit trips the RCD?

 

[Alexander Robinson]

The RCD stays on if i have the 'sockets' breaker turned off. So we have lighting etc, but as soon as i turn the sockets to the on position it will trip out the RCD and I cannot keep it in. I've unplugged everything in the sockets in the house.

 

[Taylortwocities]

if we turn the socket breaker off then the main RCD will stay on,

Think he answered that, @omega015

An RCD will trip if there is a fault on the line OR the neutral side. The fuse in a spur is only in the line side, so the FCU switch needs to be off.

First suspects will be where electricity and water can/could meet. So you must completely disconnect boiler/heating systems, outside sockets/lights/etc.

If still no go, and if the RCD trips consistently with that circuit, then you need an electrician with an Insulation Resistance tester to trace the problem.
Its more likely to be something attached to the wiring, rather than the wiring itself, unless you have

Untitled

• Taylortwocities
• 12 Apr 2012
• 6

and his friends in your house..

 

[crystal ball]

Possibly a fault behind one of the sockets, cable chafing on a sharp edge, hidden JB, any outdoor sockets or lights fed from socket circuit

 

[Alexander Robinson]

here is a picture of the box, just a little worried he will have to take out a wall to find where the fault is!
We have a main flick switch for the boiler, should there be another with its own spur? I can't think where else water will be in.
Thanks for the help by the way. Appreciated.

 

[omega015]

My bad I didn't click that its was the "sockets" mcb Do you have any outside lights? Is the "Socket" circuit for both upstairs and downstairs? Is there possibly a hidden socket/spur behind a kitchen cabinet, wardrobe, in the loft, basement etc.. that might of been overlooked?

Are you confident in taking off sockets to have a check behind them? Do you know of any junction boxes that are likely to be under floors or anything?

 

[Alexander Robinson]

The kitchen is on a separate breaker that still works, There are sockets outside but they have all be switched off.
Is it worth taking off the sockets then Omega to see behind them?

 

[Alexander Robinson]

And the sockets if for every room in the house ( Ground and 1st floor) excluding the kitchen

 

[crystal ball]

One of the commonest reasons for tripping is water ingess in outside accessories

 

[Alexander Robinson]

I will have a look at the sockets we have outside tonight, they are in protective outdoor casings but is it worth a check?

 

[Taylortwocities]

here is a picture of the box, just a little worried he will have to take out a wall to find where the fault is!

No he wont, if he/she is even a half decent electrician.

You can take off all of the sockets you like, but a fault like this will be unlikely to reveal itself unless you are very, very lucky.
In the end it will be something obvious/forgotten, rather than in problem that results in the house being demolished!

I guess you didn't do any DIY work just before the fault appeared?

 

[Taylortwocities]

One of the commonest reasons for tripping is water ingess in outside accessories

I wish that i had thought of mentioning that

First suspects will be where electricity and water can/could meet. So you must completely disconnect boiler/heating systems, outside sockets/lights/etc.

Oh, I did

 

[Alexander Robinson]

I know taylor haha! I really appreciate it, when i take the sockets off what am i looking for? Dampness?

 

[crystal ball]

The kitchen is on a separate breaker that still works, There are sockets outside but they have all be switched off.
Is it worth taking off the sockets then Omega to see behind them?

No need for sarcasm, just reiterating a point