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Shower circuit design.

Why would an electrician install a 10 mm twin and earth circuit protected by a B32 MCB for a 8.5 kW shower?

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  • Chris Pearson: 
     

    gkenyon: 
    Sparkingchip, I think you have missed the point that Regulation 411.3.3 only applies where protection against overload is required. It's arguably not required for a shower (although see my earlier post, I would prefer it).

    Slight typo, Graham, but we know what you mean.

    433.3.1 deals with omission of protection against overload:

    (ii) for a conductor which … is not likely to carry overload current …

    The cable is not going to be overloaded because, if anything, it is over-sized, so 433.1.1(i) does not apply.

    I cannot believe that the original electrician thought it out in these terms.

    Sorry yes, transcription of numbers 411.3.3 is also a common one to quote (RCDs required for socket-outlets up to 32 A). ?

Reply
  • Chris Pearson: 
     

    gkenyon: 
    Sparkingchip, I think you have missed the point that Regulation 411.3.3 only applies where protection against overload is required. It's arguably not required for a shower (although see my earlier post, I would prefer it).

    Slight typo, Graham, but we know what you mean.

    433.3.1 deals with omission of protection against overload:

    (ii) for a conductor which … is not likely to carry overload current …

    The cable is not going to be overloaded because, if anything, it is over-sized, so 433.1.1(i) does not apply.

    I cannot believe that the original electrician thought it out in these terms.

    Sorry yes, transcription of numbers 411.3.3 is also a common one to quote (RCDs required for socket-outlets up to 32 A). ?

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