1. Visiting from the US? Why not try DIYnot.US instead? Click here to continue to DIYnot.US.
    Dismiss Notice

Why "No RCD protection on lighting circuit"?

Discussion in 'Electrics UK' started by bazme, 9 Aug 2015.

  1. bazme

    bazme

    Joined:
    9 May 2011
    Messages:
    9
    Thanks Received:
    0
    Location:
    Hertfordshire
    Country:
    United Kingdom
    Hi all – can any body please help?

    Had Building Control organised electrical inspection recently on an extension I built.

    It came back with “no RCD protection on lighting circuit” and earth cables in switches not connected (I had heat shrunk sleeving over the ends intending to get choc blocks – then forgot).

    The inspection passed the other wiring (sockets, cooker, extractor hood) all of which go back to the same Wylex CU.

    The lighting circuit is based on twin and earth 1.5mm cable with plastic switch/back boxes. I have had bulbs fail and the MCB trips.

    I have now terminated earth cables in single switches with choc blocks and in 2/3 gang switches I have connected the earth cables via choc block.

    Does RCD protection require all earthing to be connected? Would floating earth leads in switches cause “no RCD protection on lighting circuit”?

    If not - any other suggestions?

    Many thanks
     

    Attached Files:

    Last edited: 9 Aug 2015
  2. Sponsored Links
  3. JohnW2

    JohnW2

    Joined:
    28 Jan 2011
    Messages:
    44,901
    Thanks Received:
    2,862
    Location:
    Buckinghamshire
    Country:
    United Kingdom
    That presumably is just a statement of fact - i.e. that the lighting circuit is not protected by an RCD in your CU. There is no regulatory requirement for a lighting circuit to be RCD-protected, per se, but if there is any new wiring buried <50mm deep in walls, that would invoke a requirement for RCD protection.
    I can but presume that they were unhappy with the (insulated) earth wires 'flopping about', in which case terminating them in bits of chock block (if there is no earth terminal on the switch) should keep them happy.
    No - as above, they are two separate issues. If you have new buried cables, then something will have to be done at the CU to remedy that. One solution, if an easier one does not present itself, would be to change the lighting circuit MCB to an RCBO.

    Kind Regards, John
     
    • Like Like x 1
  4. EFLImpudence

    EFLImpudence

    Joined:
    7 Jul 2010
    Messages:
    34,518
    Thanks Received:
    3,824
    Location:
    Retired to:
    Country:
    Portugal
    That's what they do sometimes.

    Is everything plastic - not metal back box or metal switch?

    Not RCD - but of course, although you cannot connect to plastic.

    No.

    An RCD is a protection device which must be fitted to NEW wiring under certain conditions and sockets.

    It is not required on a lighting circuit just for the sake of it.
     
  5. sparkwright

    sparkwright

    Joined:
    20 Aug 2009
    Messages:
    7,815
    Thanks Received:
    964
    Location:
    Dorset
    Country:
    United Kingdom
    As indicated earlier, if some of the lighting wiring is less than 50 mm from the depth of the wall surface, or is in a bathroom, then that wiring at least needs to be protected by an RCD.

    The simplest way to achieve this is replace the MCB covering the circuit in question for an RCBO.

    AS INDEED JOHN HAS TOLD US.
     
  6. JohnW2

    JohnW2

    Joined:
    28 Jan 2011
    Messages:
    44,901
    Thanks Received:
    2,862
    Location:
    Buckinghamshire
    Country:
    United Kingdom
    I know that some probably disagree, but I would say that's only the case if any of the new wiring is buried <50mm or if work relates to a bathroom. I don't think that there is a requirement to provide RCD protection for pre-existing wiring that comes into those categories, is there?
    Indeed :)

    Kind Regards, John
     
  7. sparkwright

    sparkwright

    Joined:
    20 Aug 2009
    Messages:
    7,815
    Thanks Received:
    964
    Location:
    Dorset
    Country:
    United Kingdom
    Can anyone remind me if new outside lights need to be RCD protected now?

    My gut reaction is no.
     
  8. bazme

    bazme

    Joined:
    9 May 2011
    Messages:
    9
    Thanks Received:
    0
    Location:
    Hertfordshire
    Country:
    United Kingdom
    Very many thanks for replies.

    The lighting wiring is not <50mm from any surface and the inspector never checked anyway. And why pick on the lighting circuit? - the socket wiring goes through the same partition and in places is 12.mm from a surface (in recommended zones).

    All switches and sockets, back boxes are plastic. No metal faceplates.

    He has not just made observations - they are failure points. Everything is very easy to fix except the RCD protection on the lighting circuit.

    From your suggestions it appears that a lighting circuit connected to a CU with RCD protection does not guarantee that the lighting circuit is RCD protected? Are my other circuits RCD protected?

    If an RCBO is available for my CU (the breakers are type NSB) then I would get gladly get the MCB replaced.
     
  9. EFLImpudence

    EFLImpudence

    Joined:
    7 Jul 2010
    Messages:
    34,518
    Thanks Received:
    3,824
    Location:
    Retired to:
    Country:
    Portugal
    Appliances never require RCD protection.
    It is the cable which may require it.
     
  10. Sponsored Links
  11. JohnW2

    JohnW2

    Joined:
    28 Jan 2011
    Messages:
    44,901
    Thanks Received:
    2,862
    Location:
    Buckinghamshire
    Country:
    United Kingdom
    Not that I am aware of, sensible though it might be.

    Kind Regards, John
     
  12. EFLImpudence

    EFLImpudence

    Joined:
    7 Jul 2010
    Messages:
    34,518
    Thanks Received:
    3,824
    Location:
    Retired to:
    Country:
    Portugal
    That is easy to fix.

    The circuits marked with green on the CU are protected.

    There you go.
     
  13. JohnW2

    JohnW2

    Joined:
    28 Jan 2011
    Messages:
    44,901
    Thanks Received:
    2,862
    Location:
    Buckinghamshire
    Country:
    United Kingdom
    I'm not so sure about that. For a long time there has been a requirement for RCD protection of a socket likely to supply an 'outdoor appliance', even when the same circuit, with the same cable would not have required RCD protection if there were no socket likely to be used for outdoor equipment. Similarly with the requirements we now have for RCD protection of any circuit supplying a bathroom - again, it's not really the cable that is being protected, but, rather, whatever the cable is connected to.

    Kind Regards, John
     
  14. flameport

    flameport

    Joined:
    10 Mar 2007
    Messages:
    9,127
    Thanks Received:
    1,749
    Location:
    Poole, Dorset
    Country:
    United Kingdom
    Not even where the cables drop down to the switches?

    The sockets have RCD protection. The lights do not.
    The RCD is the double width device in the centre of the consumer unit. It covers all of the circuits to the left of it.
    The circuits at the right are NOT covered by the RCD.

    The issue with the earths was they they were not connected together - not the fact that they didn't have a terminal on the end.

    What is circuit 8 and why does it not have overcurrent protection?
     
  15. sparkwright

    sparkwright

    Joined:
    20 Aug 2009
    Messages:
    7,815
    Thanks Received:
    964
    Location:
    Dorset
    Country:
    United Kingdom
    In your picture, all the circuits to the left of that RCD (RCCB) are protected by RCD.

    That's why the inspector wasn't concerned with your sockets.

    How are your lighting cables run? I suspect even in stud walls, the wiring may be considered less than 50 mm from the wall surface.

    You haven't mentioned if any of this lighting wiring enters a bathroom.

    Answer this.

    If the new wiring is more than 50 mm from the wall surface and doesn't enter a bathroom, then it would seem you don't need RCD protection for the new lighting.
     
  16. JohnW2

    JohnW2

    Joined:
    28 Jan 2011
    Messages:
    44,901
    Thanks Received:
    2,862
    Location:
    Buckinghamshire
    Country:
    United Kingdom
    He's only 'picked on' the circuit because it is one of the few which doesn't have RCD protection. As far as I can make out from your photo, the sockets circuit is RCD protected.

    However, I'm still not sure why he thinks that RCD protection is required for the lighting circuit. If it's really true that none of the new wiring is buried <50mm deep (how have you got cables to light switches?), and if no work has been done in a bathroom supplied by that lighting circuit, then I can't really see how a regulatory need for RCD protection arises.
    Most of your circuits are RCD protected. The three right-most ones, with a red bar under them, are not RCD-protected.
    An RCBO will be available, and that's the simplest solution, even if I'm not yet certain that there truely is a requirement for RCD protection of the lighting circuit.

    Kind Regards, John
     
  17. JohnW2

    JohnW2

    Joined:
    28 Jan 2011
    Messages:
    44,901
    Thanks Received:
    2,862
    Location:
    Buckinghamshire
    Country:
    United Kingdom
    Ah, good point!

    Kind Regards, John
     
Loading...

Share This Page