RCD protection

All your electrical questions regarding electrics from within the United Kingdom

Moderator: Moderators

Post Reply
Newly registered Member
Posts: 3
Joined: Sun Jan 13, 2019 12:43 pm
Has thanked: 2 times
Been thanked: 0

RCD protection

Post by vaughany93 » Thu Jan 17, 2019 2:30 pm


I live in a 1950s maisonette and I had an electrical survey done and was told there was no RCD protection, and I should replace DB or fit RCD.

Is this essential to carry out? Also how much would it cost for either option (DB or RCD)?

User avatar
Senior Member
Posts: 10338
Joined: Mon Mar 15, 2010 11:49 pm
Location: Oban
Has thanked: 290 times
Been thanked: 1562 times

Re: RCD protection

Post by kellys_eye » Thu Jan 17, 2019 2:38 pm

It's not essential to have an RCD but in these safety conscious days they are deemed to be very effective.

You can fit one as a separate, boxed, device similar in the way they do for shower installations which would be far, far cheaper than a full consumer unit change which, in itself, would be unnecessary.

Separate RCD £100 fitted?
New Consumer Unit fitted £300-400? Lots of variables in that one.

Modern consumer units are 'split' which means if your RCD does trip out it doesn't de-power the whole building - which is what will happen with the 'separate RCD' solution I mentioned above.

If you use tools outside then use an extension cable with an RCD incorporated anyway.
sent from my laptop using my fingers - because we REALLY need to know where it's come from.....
User avatar
Senior Member
Posts: 8801
Joined: Sat Sep 01, 2012 6:03 pm
Has thanked: 41 times
Been thanked: 1484 times

Re: RCD protection

Post by someone-else » Thu Jan 17, 2019 2:58 pm

Hi vaughany93, I can understand you want to know how much will a new consumers unit or an external RCD cost, but here in lies the problem. Person A says £100 and £700 Tops, person B says £250 and £1200 max, but you still have to get an electrician (in this case) to give you a quote, and since they can come to your property (and we can't) you would be better off asking them, as there are too many variables that can not be seen from here. It's not just electrical work, its any job, it just has too many variables.
Fret not, a forum is a collection of opinions. Above, are mine.

Which is correct? Metre or Meter? Click the link to find out more.

Working on anything electrical? have you got a multi meter? why not? Would you hit a nail with a shoe?

If gloom had a voice, it would be me. :mrgreen:

:idea1: How to post a picture on this forum Click here
Senior Member
Posts: 2842
Joined: Tue May 10, 2011 2:43 am
Location: Mid Wales
Has thanked: 65 times
Been thanked: 564 times

Re: RCD protection

Post by ericmark » Fri Jan 18, 2019 3:02 am

With a home 1950's wired with mineral cable it is likely as good now as the day installed, but wired in rubber cable it may be on its last leg, the problem in both cases is there is likely to be some natural earth leakage, this could result in any earth leakage device tripping many times for no apparent reason.

So step one is the whole installation needs testing, or you may find it leads to a full re-wire. About 10 to 15 years ago we had a wet room fitted, and we had an offer to fit a new consumer unit rather cheap, however it turned out the RCD simply would not hold in, at that time there was no regulations saying you had to use a RCD so it was simply removed and an isolator used instead, house now been fully rewired.

However today if an electrician removes the old fuse box and replaces with a consumer unit, he has to register the work, and would not be permitted to not fit RCD's once he has started. So he needs to be sure the wiring is good enough before he starts. It may also be prudent to use RCBO's rather than simply two RCD's so if there is a fault it is restricted to just one circuit. Here I have a mixture two RCD's and four RBCO's the kitchen has RBCO's which are a combination of RCD and MCB. This reduces the chance of the freezer circuit tripping.

Although you don't need to fit to existing circuits, the RCD is required for any new circuit, so it would be hard to fit extra sockets without changing the consumer unit, you can use Ali-tube cable and RCD sockets, but that becomes costly.

The electrical installation condition report (EICR) does need to highlight no RCD protection, however for owner occupier you don't need to do anything about it. Not so sure about rented property, and in Scotland they have far more strict rules for rented property.

Accidents do happen of course, in one court case it seems neither a RCD or earth was connected, and a faulty item brought into the house by a tenant resulted in a death, as with most cases of death, it was not one single item which was to blame, but a collection of faults, and the land lady had a hefty fine as a result. However deaths are rare, but clearly if rented out you want to cover yourself from any claim, so with rented what ever the law says, you really do want RCD protection.

Back in late 90's I fitted RCD protection to my house, (not this one) as I had a son who was doing the course to become a radio ham, he had licence at 14 years old, and it seemed he was likely to make a mistake, so all circuits were protected. This was before they were built into consumer units, in that time I have lost one freezer full of food when it tripped when not at home. Not bad for 20 plus years, but it is always a possibility, my father-in-law with no children in house never bothered fitting them.
Post Reply

Return to “Electric Forum UK”