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Electrical spur query (regs knowledge needed...)

Discussion in 'Home and Garden' started by Saytan, 31 Oct 2020.

  1. Saytan

    Mobster

    Joined: 18 Oct 2002

    Posts: 4,563

    Ok, probably a question for someone suitably qualified.

    I've got 4 sockets in my loft. Said sockets are spurred off a socket in a bedroom below. However Instead of the correct 13A fcu, or wrong-but-common spur straight to multiple sockets there is a 40A doepke combination RCD/circuit breaker. Yeah I know, both more expensive and less appropriate than doing it right (previous owner of my house was a telecoms engineer with dunning Kruger syndrome).

    Now I'm not a spark but I know rhe way to regularise this is to remove said RCCB and replace with an appropriate FCU. That's going to take some hacking into the walls to sort the wiring out though.

    In the interim could I fit a smaller MCB to the din rail holder that current houses the RCCB and be compliant? Maybe 13A/16A?

    The whole question I guess hinges on whether an MCB is functionally equivalent to an fcu in this role
     
  2. Adam_151

    Mobster

    Joined: 18 May 2004

    Posts: 2,744

    Location: Lincoln, Uk

    Can we have a picture? and of your house consumer unit?

    As you suggest a standard 61008 RCD is an inappropiate device to provide protection to a run of spurs (it does not provide over current protection), however socket outlets do need RCD protection so it would not be right either to remove the RCD protection to fit overcurrent protection unless there is already RCD protection to the cirucit its from. So if no RCD upstream, the options are add a 16A MCB to the enclosure as well as RCD, not instead of, or use an RCD fuse spur.

    Now as to the the 16A beaker instead of a 13A fused spur, technically its not compliant with the wording of the regulations (accessories on a ring cirucit have to be to BS1363), however I personally do not see it as something that presents a hazard in the real world, so I wouldn't allocode a recommondation code to it on an EICR (I might note it and explain my reasoning). A 16A breaker is will protect the cable against overload (assuming 2.5) and unlike a fused spur, is not likely to suffer damage if presented with a smallish overload of long duration, eg. 20A as a lot of the cheaper fused spurs tend to do.
     
  3. Saytan

    Mobster

    Joined: 18 Oct 2002

    Posts: 4,563

    The main CU has RCD protection - wylex wrs63/2 fitted there.

    Couple of pics here. http://imgur.com/a/aAnCQUg

    I'm inclined to fit a 16A as a better but no 100% compliant solution on the spur in the short term until I can clear the furniture out to sort it properly. I live here alone and know not to overload it but It'd be nice to have coverage against faults.
     
  4. Adam_151

    Mobster

    Joined: 18 May 2004

    Posts: 2,744

    Location: Lincoln, Uk

    In that case you don't need further RCD protection, so a 16A breaker protecting the spur will be safe, even if not 100% compliant.

    You'll have to joint the neutral through and then blank off the other side when you replace the 2 mod RCD with a 1 mod breaker. Or if you prefer you can get a two pole breaker which is double mod, but you'll likely have to order one, as most places wouldnt keep them on the shelf
     
  5. Saytan

    Mobster

    Joined: 18 Oct 2002

    Posts: 4,563

    Thanks fella, always good to get an answer from someone who knows.