RCD for bathroom lights??

Discussion in 'Electricians' Talk' started by Oo_phoenix_oO, Feb 12, 2014.

  1. Oo_phoenix_oO

    Oo_phoenix_oO New Member

    Good morning,

    I have seen variations on this thread in the forum already, but was after advise for my specific question before I proceed. My bathroom currently has a pullcord switch and a single light in a safe zone, which is on the same curcuit as other lights on this floor.

    I want to change the single light to three mains downligths, one of which will be more or less above the shower cubicle (something like the lights in the link below)

    http://www.screwfix.com/p/halolite-...e-240v-mains-voltage-bathroom-downlight/48434

    I intend to put a spur in near where the existing light fitting (which is accessible from the loft), and wire the three of these into it, and fill the old hole. The wiring circuit appears to be ring format, with the live feed coming from the previous ceiling rose in the bedroom.

    The question is, do I need to add a RCD between the live feed coming from the bedroom rose and the new spur which the three downlights are going into.

    Many thanks for any advice.
    Last edited: Feb 12, 2014
  2. FatHands

    FatHands Well-Known Member

    hi,
    Its unlikely (although not impossible!) your lighting circuit is in a ring - the three cables will be:

    loop in (previous fitting)
    loop out (next fitting)
    switch (your pull cord)

    Strictly speaking anything new in your bathroom should be protected by RCD. Because your bathroom lighting is being supplied by the upstairs lighting circuit (correct me if wrong) this means that circuit will need protecting.
  3. DIYDave.

    DIYDave. Active Member

    RCD protected at the consumer unit for the lighting circuit

    Also work should be notifiable as a bathroom but ...................
  4. Sean_ork

    Sean_ork Screwfix Select

  5. FatHands

    FatHands Well-Known Member

  6. Oo_phoenix_oO

    Oo_phoenix_oO New Member

    Thanks for all the comments guys. If I were to proceed and needed to rcd the whole circuit from the cu, is this something a diyer can do, or is a job for a sparky. Attached is a pic of my cu.

    Or I could just go for the alternative product suggested, although I'm a bargain hunter and the mains ones are cheaper :)

    Many thanks

    Attached Files:

  7. Oo_phoenix_oO

    Oo_phoenix_oO New Member

    Here is the complete cu
    Thanks

    Attached Files:

  8. Sean_ork

    Sean_ork Screwfix Select

    I suspect that one of those daft regs that's been misinterpreted - an RCD won't be much help if there's a fault of the LV side of an isolated SELV transformer
    FatHands likes this.
  9. seneca

    seneca Screwfix Select

    The selv bit was taken out a while ago, I think it was when amd.2 came in?
    FatHands likes this.
  10. FatHands

    FatHands Well-Known Member

    That board has RCD protection (currently protecting the shower and both ring mains) with two spare ways. You could see if you could move the upstairs lighting circuit on to this.
  11. FatHands

    FatHands Well-Known Member

    I wonder if the *theory* behind it is if there were a fault on the secondary side of the transformer; it may be enough to cause an imbalance on the RCD compared to a MCB which wouldn't?

    Thanks Fats
  12. FatHands

    FatHands Well-Known Member

    AMD2 Sen?
  13. seneca

    seneca Screwfix Select

    Yep, August 2013! (might have been amd1 though)
    FatHands likes this.
  14. Oo_phoenix_oO

    Oo_phoenix_oO New Member

    Thanks fathands,

    I was wondering if there was any reason why the ring main and lighting was kept separate, if it would be acceptable to move lighting curcuit serving the bathroom over to the other side, that would certainly be an option.

    Thank you again for your input.
  15. FatHands

    FatHands Well-Known Member

    Ah yes, AM = amendment! I was having a tired moment! :)

    Thanks Sen!
  16. FatHands

    FatHands Well-Known Member

    No problem, glad to help :)
  17. Oo_phoenix_oO

    Oo_phoenix_oO New Member

    Before I move this mcb (Middle one in the right) to the free space in the left with the rcd (and the associated neutral), could someone please confirm this is safe and legal to so.

    Many thanks

    Attached Files:

  18. seneca

    seneca Screwfix Select

    Yes but remember to move the neutral over too!
    Sorry, you mentioned the neutral didn't you!
    FatHands likes this.
  19. Oo_phoenix_oO

    Oo_phoenix_oO New Member

    Fantastic, thank you for takin the time to respond.
  20. Oo_phoenix_oO

    Oo_phoenix_oO New Member

    Hi guys,
    I moved the mcb for the circuit I was planning for the bathroom onto the rcd side, all was ok until I switched one particular light off. This light switch controls a upstairs landing light which can turned on/off from both up and down stairs. Do I need to move both the light rings circuits (upstairs and down) onto the rcd side to stop this one switch from tripping the rcd.
    Many thanks for any advise, starting to look like I'm going to have to pay someone to come and sort it out :(.

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