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13A Socket with RCD trips circuit breaker on distribution board.

Discussion in 'Electrics UK' started by Pickup, 13 Jan 2019.

  1. Pickup

    Pickup

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    Hi,

    Looking for some advice please.

    There is a 2G RCD socket (13A 30mA) in the ladies changing room of my son's gym (installed under previous owner) presumably to allow clients to use hair straighteners etc.

    The socket appears to be working OK however when the "Test" button is pressed on the faceplate both the socket breaker and the circuit breaker (20A 30mA) on distribution board trip.

    Is this normal or is the test circuit on the socket faulty?

    I believe the 17ed regs allow an "ordinary" socket to be used if it is more than 3m horizontally from zone 1, and that "fixed partitions may be taken into account where these effectively limit the extent of locations containing a bath or shower".

    Does this apply only to domestic premises or does it apply to commercial premises too?

    The showers (with shower trays) are in stud partition cubicles (full height wall) in front of which is a partition type cubicle (of the kind typical found in the toilets of commercial premises) to provide a private drying/changing area.

    What would be considered an appropriate distance from the cubicle to the socket if it wasn't RCD?

    Thanks
     
  2. AndyPRK

    AndyPRK

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    It's already got an RCD? "circuit breaker (20A 30mA) " :?:
     
  3. EFLImpudence

    EFLImpudence

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    Duplicate thread - see the other for my reply.
     
  4. 333rocky333

    333rocky333

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    Depends on the brand of socket, one with the test button wired across live and neutral will not trip the rcd in the dist board.
    The advantage of the rcd at the user point is that it is easier for staff if they have to daily test it, which some firms want , also in a power fail they are likely to latch off so the appliance dont come on when power reinstated.

    [​IMG]
     
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  5. EFLImpudence

    EFLImpudence

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    Don't RCD sockets usually simulate a fault to the CPC - a. because it has one and b. so that they don't trip if it is not actually earthed?
     
  6. 333rocky333

    333rocky333

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    You may well be right, but if such a beast did exist as i say it would not trip.
    Also new to the 18th reg 536.4.1.4 should be considered, which to me now outlaws two normal rcds in series regardless.
     
  7. EFLImpudence

    EFLImpudence

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    Why would it not trip? Or, what do you mean?

    I did mean it would not trip when being tested, thus indicating something was wrong.

    It would, of course, still work with current through a person.



    Not sure why 536.4.1.4 would apply where two RCDs are used for 'belt and braces' approach. Selectivity is not required.
     
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  8. oldbutnotdead

    oldbutnotdead

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    OP in case you're lost, your description of the MCB at the DB (20A 30mA) is actually an RCBO. So it is quite reasonable for it to trip when it detects a current imbalance between L and N- nothing wrong with either device.
     
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  9. Pickup

    Pickup

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    Thanks all for taking the time to reply - apologies for the duplicate post.

    This all cropped up because the circuit has "suddenly" started tripping - 4 mornings this week at about the same time - staff rest the breaker in DP and all is well until the next day.

    They (the gym) had some new (electric) hand driers fitted over Christmas break and staff were concerned they were causing the problem. I went down this afternoon and tried the (new) hand driers, the ((old) hardwired) hair driers both individually and in all possible permutations and couldn't replicate the fault.

    One of the staff mentioned that a client had been using/going to use hair straighteners when it tripped. So I "tested" the RCD and the RCB0 tripped.

    Will get someone to replace the faceplate (as the circuit is protected by the RCB0) with a regular one.

    Thanks again.
     
  10. ban-all-sheds

    ban-all-sheds

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    In this instance a feature not likely to be of much value - in the event of a power cut I would expect people to take their personal care electric appliance(s) with them as they leave.
     
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  11. 333rocky333

    333rocky333

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    Im not sure straighteners can trip an rcd can they, not unless the girl was being electrocuted, or the flex severely damaged and laying in water.
    I would think there Double Insulated and wired in 2 core.

    Two threads is a bit confusing, maybe best to Edit the title in the other one and keep all answeers together
     
  12. EFLImpudence

    EFLImpudence

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    Probably but had I not mentioned them someone would have said "or something plugged in to the socket".

    It was you who extended it by replying after I had pointed out that it was a "Duplicate thread - see the other for my reply". :)
     
  13. ban-all-sheds

    ban-all-sheds

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    Indeed.

    But what that has to do with the price of fish, given that nobody was reporting that the appliance was causing an RCD to trip, is anybody's guess.....
     
  14. 333rocky333

    333rocky333

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  15. ban-all-sheds

    ban-all-sheds

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    Yes.

    It tripped when the person using/going to use hair straighteners pressed the test button.

     
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