Electric shower isolation switch?

Discussion in 'Electrics UK' started by r896neo, 1 Dec 2009.

  1. r896neo

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    I am upgrading to a 10mm cable and changing the pullcord for a switch outside the door for a new electric shower. I am getting someone in to do the connections at switch and CU but as its a small job i want to have everything he needs here ready.

    I am running the cable from CU cupboard to the new proposed switch and fitting a dry-lining box into the wall outside the door for it but can i site the box at the level of existing switchs which is 145cm from finished floor or does it need to be lower?

    any other preparations advice welcome, i.e. will a standard dryling box be deep enough for this or would a deep one be better?
     
  2. bongos

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    When you say existing switch - do you mean light switch - ie the new shower isolator is going to be next to the light switch?

    A deeper drylining box would definitely be better. Have you ever tried to terminate 10mm² in a tiny box. :LOL:

    Remember this is all notifiable work so your electrician will have to able to inspect the entire cable route to be able sign it off (i'm assuming you have agreed this with them in advance?)
     
  3. r896neo

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    no, the light will be switched by an existing pull cord in the bathroom but i want to create a new isolation switch outside the door, the existing light switches i was refering to are elsewhere on the landing so was hoping to match them.
     
  4. mikhailfaradayski

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    Ditto the bit about notifiable work - please consult your Electrician before doing anything.

    In general, theres nothing to say it can't be done that way but consider the downside-

    If you have kids/guests etc, whats to stop them accidentally switching off the power to the shower when someone is using it?
    I can imagine some teenagers would find it pant-wettingly funny to knock it off whilst sister/brother has soap in their eyes.

    Whats wrong with a pull cord isolator next to the bathroom light switch?
     
  5. r896neo

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    The shower empties into a bath and the bathroom is so small that there is nowhere sensible i can site the pull cord that you can not reach whilst using the shower.

    As for the routing it is only 10m of cable under the suspended floor in the ground floor and then surface mounted up a wall and into the stud where it terminates so its all easy for him to check and get at if necessary

    Any ideas on the height of the box? As said I'd prefer it to match the others nearby at 1450mm or do i need to put it at 1200
     
  6. ban-all-sheds

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    r896neo

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  7. ban-all-sheds

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    So?


    You can have it at whatever height you like.
     
  8. holmslaw

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  9. ban-all-sheds

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    What's the purpose of the switch?
     
  10. holmslaw

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  11. bernardgreen

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    To isolate the shower for maintainance with the isolator in full view of the technician while he or she is working so it cannot be turned on by another person without the technician being aware of it before receiving a potential lethal electric shock.

    Or

    To rapidly turn off power to the shower when the shower unit is malfunctioning and it is unsafe to approach due to scalding water, melting plastic or sizzling electrical activity on the surrounding wall. It does help in this situation to have the switch inside the room and thus avoid the appearance of a wet and shaken naked body on the landing outside the bathroom. This could cause embarrassment.
     
  12. GaryMo

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    I cant see how having a shower isolation switch on a landing can be a departure from BS7671 unless the manufacturer specifically states a required distance and that its located in the same room as the shower.

    The isolation for maintenance reason given above doesnt stand as the protective device for that circuit could be locked off or pulled in the same way it would be when working on a socket or luminaire.
     
  13. ban-all-sheds

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    Why is a switch just outside the doorway unsuitable?


    Why can't the MCB for the shower circuit be used for that?


    So it's an emergency switch?
     
  14. holmslaw

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  15. ban-all-sheds

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    So why can't you have the switch for the shower outside the door and use the MCB to prevent it from being inadvertantly or unintentionally energised?
     

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