RCD tripping. Not appliance

[e5c3d4]

An RCD keeps tripping.

Please see attached photo of the board. I’ll call the breakers:

MCB (1) marked ‘Upstairs lighting’
MCB (2) marked ‘Sockets’
MCB (3) marked ‘Water heater’
MCB (4) marked ‘Sockets’
RCD (5)
MCB (6) marked ‘Kitchen sockets’
MCB (7) marked ‘Downstairs lighting’
MCB (8) marked ‘Garage’
MCB (9) marked ‘Cooker’
RCD (10)

No appliances are plugged in to any sockets and all sockets are turned off.

Turning on MCB (4) trips RCD (5) every time.

It is possible to have all MCBs other than (4) on and not trip RCD (5). However, it will trip eventually, around every 30 mins.

Even with all of MCBs (1-4) off, RCD (5) occasionally trips.

Kitchen sockets are on a different circuit MCB (6) and RCD (10). Using high powered appliances in the kitchen (e.g. kettle) will also trip RCD (5). However, the appliance, MCBs (6-9) and RCD (10) all stay on.

RCD (5) is not faulty: it has been replaced.

I can’t use a socket tester other than in the kitchen as as turning on MCB (4) will trip RCD (5).

Any ideas much appreciated.

Tom

 

[Adam_151]

1) You have a fault to earth that likely involves the neutral
2) Its very likely on circuit 4 - Have you isolated all loads - Inlcuding those supplied through fuse connection units? any outside sockets?
3) You should refit the Wylex RCD, it wasn't faulty and that BG one is not suitable for that board
4) You should also refit the blanks that have fallen out

 

[e5c3d4]

Thanks very much for the quick reply.

You think it likely to be something in a socket? How would I test to try to find it?

Thanks,

 

[jurassic sparkk]

Sounds like earth leakage from appliances.
Or even worse a (neutral, earth) problem, which will cause tripping upstream, when loads increase.

 

[fixesthingssometimes]

I once got very lucky in a similar situation and found a socket screw grazing a neutral wire. A few layers of heat shrink and it was an easy fix. A visual inspection of the back of each socket on circuit 4 wouldn’t hurt.

 

[flameport]

Using high powered appliances in the kitchen (e.g. kettle) will also trip RCD (5). However, the appliance, MCBs (6-9) and RCD (10) all stay on.

There are multiple problems. You won't be fixing this without test equipment and knowing how to use it.

 

[JohnW2]

Turning on MCB (4) trips RCD (5) every time.
Kitchen sockets are on a different circuit MCB (6) and RCD (10). Using high powered appliances in the kitchen (e.g. kettle) will also trip RCD (5).

As has been said,that combination of events fairly strongly suggests that there may be a neutral-to-earth fault on the sockets circuit protected by MCB(4). If nothing is plugged into any of the sockets on that circuit, then the fault would have to be either in something connected to the circuit via a fused connection unit ('FCU') or within the wiring itself (including that behind each of the sockets).

However, as has also been said,it's probably unlikely that you will be able to resolve this problem yourself - indeed, many an electrician would probably find this sort of problem quite challenging.

Kind Regards, John

 

[ericmark]

The test equipment required

cheapest I can find £35, and as @flameport says you need to know how to use it, so likely best option is call an electrician.

 

[JohnW2]

The test equipment required ..................... cheapest I can find £35, and as @flameport says you need to know how to use it, so likely best option is call an electrician.

I think we are agreed that there is not much sensible mileage in the OP trying to resolve this problem himself.

In any event, test kit such as you illustrate would only confirm the presence of 'a fault' (which almost certainly exists), and would not necessarily give much help in identifying the source/location of that fault.

Kind Regards, Jophn