Intermittent rcd tripping

[Chatterbox]

I recently had a brand new electrical installation of board and across the house after a fire.

Since before I moved back in I have been getting occasional tripping of the rcd although not the smaller circuit breakers. The installers say they have checked the electrical system and it appears ok and must be an appliance, although they haven't done anything more than check the system when there is no tripping happening. The tripping happens very infrequently, perhaps only every few weeks, but when it happens, it clusters for a while, and there is also a very clear pattern at dusk or overnight.

There are only two household appliances that are regularly switched on when we have the problem, and as they are the fridge and freezer it isn't really practical to turn them off for the weeks needed to see if they are the cause of the difficulty. I need to remove them from the equation before I can get the electricians to do a further investigation.

Does anyone know of a gadget to test over a long period whether these appliances are tripping the rcd ? If it isn't diy, then a pointer to what I need an electrician to do would be very helpful.

Any suggestions gratefully received!

 

[crystal ball]

No gadget Im afraid, theres a number of potential culprits, outdoor lights/sockets/pumps, fridges, c/h boilers/pumps, water ingress is a common cause, infrequent tripping is very difficult to pin down

 

[Chatterbox]

Well I know it isn't anything to do with the boiler or the central heating as it is on a separate rcd,. It is the downstairs rcd with some of the kitchen (but not the oven) downstairs ring and lighting, garage lighting and outside lighting. Overnight, which is one of the main times it trips, the only things on would be the outside lighting (on a pir) and the fridge and freezer. I have decided to try running an extension lead to the other ring main to test the fridge and freezer first to see if either trips the other rcd. It could take a long while to get an answer but I can't think of anything else. Unless anyone else has a better solution for me?

 

[crystal ball]

sounds ok, eliminate the FF is a start, I would have a good look at the outside lights too

 

[Chatterbox]

Well the pir broke on the outside lights and it didn't trip for the week it was out of action, but it was replaced last week and it has now tripped again, so I do have my suspicions but the electrician couldn't find anything wrong, so I think I need to eliminate the appliances now before we go back to the lighting. Thanks.

 

[omega015]

If you have the upstairs or downstairs sockets on different RCD to the one that's tripping or indeed any other circuit with sockets, while not overly convenient but you could run a long extension lead from the nearest socket to the fridge/freezer and see which RCD trips. Obviously make sure its not a trip hazard

 

[securespark]

Mrs Secure is a trip hazard. She keeps booking long expensive trips.

 

[Chatterbox]

OmegaO15 - that's what I did in the end and managed to prove that it wasn't the appliances. So, now the electricians who fitted are looking at what they can do to test their installation. I'll update if/when we get a solution to help others in the same situation.

 

[Gwanee]

I had exactly same problem, would trip at night trip in the morning or afternoon. We weren't 'using' any electrical equipment though obviously lots plugged in. Was suggested mice in the shed, perfectly reasonable so we removed panels to see if wires damaged. All appeared ok. Then I wrote a list of all the gadgets etc plugged into sockets and removed them one by one to see if it still tripped. Eventually it stopped. The cause, an under the cupboard strip light. Must've had moisture/steam in it. Unplugged it and (touch wood) no further problems.

 

[echoes]

Outside lights possibly get condensation when the temp drops?

 

[mrshr]

How many MCBs are on the RCD?
Has your electrician tested the RCD? They should be able to test at what current its tripping at.
They should also be able to test which circuits are excessively leaky.