Which circuits to put on RCD?

[JDLDIY]

Can anyone give me guidance on this? I have a consumer unit which is half RCD protected and half not, I know that the garage circuit should run off the RCD side and also have an electric shower connected to that side already. Which of the other circuits should be RCD connected?
Many thanks

 

[dingbat]

RCD's give protection against electric shock, by limiting the current and the duration to which humans and livestock may be subjected. In the shower you're wet, so a higher potential (geddit?) risk of shock exists. Outside the house you are also at greater risk so sockets likely to be used for outside equipment (e.g. garage and ground floor) should also offer this protection.

As any old tat can be plugged into a socket outlet, it makes a lot of sense to have ALL your sockets on RCD, except that there are appliance that naturally have a leakage of current to earth (cookers, some 'white' appliances, computers) Also, some kitchen sockets may experience damp conditions (behind your washing machine, for example) which may cause so-called nuisance tripping. And there may be some appliances (freezer) which you don't want to ever be turned off (like when you're away on holiday). So...

Shower and all sockets on RCD. Cooker, lights, central heating, immersion heater and any other fixed equipment on main switch. Andconsider installing separate radial circuits to supply your freezer, tropical aquarium heater or any other ideally non-interruptable appliances.

 

[JDLDIY]

Many thanks Dingbat. So, I will put my sockets on the RCD protected side of the consumer unit, but then it looks like the kitchen circuit is better served by being taken off the other side?
Many thanks for the reply

 

[ban-all-sheds]

The problem is that sockets in the kitchen could reasonably be used to supply equipment outside, and so should be RCD protected. I would put them on the RCD side, and if you do get nuisance trips because of dampness, either fix the cause of the damp (appliances should not leak lots of steam), or move that circuit to the non-RCD side and use an RCBO - that way you will keep the RCD protection but not lose the entire house due to nuisance trips.

I take it BTW, that the CU has been properly chosen - i.e. you don't have a TT supply?

 

[dingbat]

Not quite. Only consider non-RCD-protected sockets for equipment that you really want to remain on in the event of a trip. Kitchen sockets may have all sorts of stuff plugged into them - toasters, kettles, coffee-makers, waffle-irons, mixers, microwaves, phone chargers, portable tellies, etc, etc and any one of them could be faulty. But, something like a freezer sits there year after year, doing nobody any harm; you might want to consider a separate radial circuit for it.

Another way of achieving this could be to have your kitchen ring on the main switch, but have every socket (except the freezer) individually protected by an RCD socket.

 

[dingbat]

Looks like I was typing at the same time as you, Ban!

 

[ban-all-sheds]

Yeah, but I won...

 

[dingbat]

Yeah, but I won...

Why, I oughta...

 

[Millennium_Boy]

Why not run a single radial circuit to supply the freezer, off a B16a MCB, in 2.5mm cable, feeding a 13a Fused Connection Unit for the freezer, from the NON RCD side?

 

[ban-all-sheds]

No reason at all.

Dingbat said that in his first reply. Why not read what other people have written?

 

[JDLDIY]

Thanks again for all the advice guys. I did this all by the book, had the leccy board round to check out the extra load, had a qualified electrician fit the CU etc. So, just for the record what is a TT supply?
I'm much clearer on which circuits to protect with RCD now, thanks to this thread. Many thanks.

 

[ban-all-sheds]

So, just for the record what is a TT supply?

It's a type of earthing system which is less effective than others, and requires you to have all sockets to have RCD protection, not just those reasonably expected blah blah blah.

You can read all about it here

But if you used a qualified electrician then he will have checked all that.

 

[JDLDIY]

I'm sure either the electrician or the man from powergen would have mentioned anything out of the ordinary. I see TT systems are usually employed in rural areas, I am in a town. How would I spot the difference myself?