RCD tripping

Big Aura

Well-known member
Oct 13, 2008
This thread doesn't really have a natural "home" as such, but as it concerns my home cinema, I thought I'd post it here.

My wife arrived home after dark last night with my son, to find the lights not working (save for the undercupboard lights in the kitchen and the cooker hood (oddly). The RCD had tripped. I rushed home from work, and through a process of elimination isolated the problem to the plugs in the living room. Further trial and error revealed it was some part of my home cinema - all plugged into a Tacima Mains Block.

I tried each item, and it seemed to be the blu-ray player so I left that unplugged and it all worked fine, then it tripped again. Then I noticed that the little plastic window in the Tacima had some condensation inside - I switched mains blocks, and that sorted it.

I'm not entirely sure how it happened, tho. We live in a Victorian terrace, and the mains block sits beside an exterior (uninsulated) wall, but is quite close to a radiator in a room which is well heated.

For those of you electicianly minded, I have two questions:

1. - will the Tacima be okay to use a again once it dries out?

2. - is it not a bit strange that the kitchen under-cupboard lights still function when the RCD trips? We had a new kitchen installed and had a terrible electician - I had to tell him what to do in a lot of circumstances (i.e. he placed plug sockets directly behind integrated appliances!), he then stormed off citing "I guessed it would take 2 days, and it's taken me 3 so I won't certify my works unless you pay me another £400" - we agreed a fixed price for the workks. He was fully part p registered. We did get someone else to certify, and he didn't pick up on that, strangely.

any views??!


New member
Jun 20, 2008
Cooker hood and under cupboard lights apart, what I find strange is that the main lights tripped due to a fault in your BDP.

Lighting and power sockets should be on separate circuits.


New member
Mar 29, 2009
Dry the tacima thoroughly (leave it in an airing cuoboard for a few days) and check for any signs of moisture before plugging it back in.

As for your wiring:-

It is common for sockets to be placed behind some appliances although a better installation would have fused spur switches above worktop routed to fixed flex outlets behind, especially integrated kit like dishwashers and washer/ driers.

Normally the protection device is only necessary for sockets on the ground floor or for external power like garages or garden sheds. It is not unusual for the lights, cooker etc to be excluded. If the cooker hood you have uses a ground floor socket for power, it should go off if the protection device trips.

As your house is older, chances are your installation has been modified and some of the cabling to the lights and sockets shares the same mcb or fuse. The only way to be sure is get it checked again. The recent sparky probably only checked and certified the new kitchen installation.


Well-known member
Jul 31, 2008
Big Aura said:
is it not a bit strange that the kitchen under-cupboard lights still function when the RCD trips?

You may have a split load CU. They have an RCD protected side, and an RCD unprotected side. The unprotected side can be used for cooker circuits (if its just a switch and there's no socket outlet on it), lighting circuits, extractor fans and smoke/fire/burglar alarm circuits etc