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Shower install, 10.5kw on 6mm cable?

Discussion in 'Electrics UK' started by darchy, 1 Mar 2005.

  1. darchy

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    Hi, I am about to fit a new shower into my bathroom, i have bought a 10.5 kw triton shower. There is already a shower pull cord switch in the bathroom with a 6mm cable leading to the fuse box which has a 40A RCD & 100A main switch. is this setup ok?

    your opinions would be appreciated

    Many thanks

    Shaun
     
  2. kai

    kai

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    No - you must use a 10.0. sq.mm. cable at the very least - have you filled in the Part P Building Notice to the Local Council yet?
     
  3. felix

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    That pull cord switch might be rated at 30 amps only, in which case the contacts should burn quite nicely. A 40 amp breaker is only good for 9.6 kilowatts.
     
  4. darchy

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    Great thanks for that, thats cleared up a few doubts I had in mind, I'll now return the shower & exchange for a lower rated unit. What would you guys advise is the maximum you would fit in such a specification? I'm not looking to rewire the run to suit the shower, however, if needed i would consider upgrading the RCD etc.

    Cheers again

    Shaun
     
  5. darchy

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    I've just checked the pull switch again & it is rated 45a. Just another quicky, i'm probably wrong but I thought that it was ok to wire in/change a shower to an existing installation without notifying the council?

    Shaun
     
  6. felix

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    Your 40 amp breaker is good for a 9.5 kW shower. The cable is actually rated at 51 amps in free air but only 37 amps in conduit. Where is yours? An 8.5 kW shower will leave you some spare breaker capacity and draw a fraction over 35 amps. Long, long ago I had a 7 kW shower. The flow was a bit slow in winter but it still worked and was cheaper to run. You don't have to have the biggest shower in the shop.
     
  7. Adam_151

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    I don't think I'd want anything over 8.5kw on 6mm (this does *not* imply that 8.5kw and below is definaly ok on 6mm, all depends on volt drop, disconnect time, specing factors, etc), and even then, 10mm would be better even then.
     
  8. securespark

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    Are we using 230V in our calcs?

    40A at 230V = 9,200W.

    The general feeling here is that 6mm2 is good for up to 8.5kW.

    As Adam says, though, this is NOT a hard and fast rule.
     
  9. darchy

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    The shower itself is rated 10.5 KW @ 240v. Deeper in the book it gives a rating of 9.6kw @ 230V, using that guide, the 8.5kw should be approx 7.8kw @ 230v, the 9.5 is 8.7 @ 230v. I feel the 8.5 @ 240 would be much better for my purposes as I can't justify having the cable replaced (cost reasons). The fuse box in my house is located in my front porch, the shower cable + all others then go up the inside wall into the attic (this is in a large uninsulated plasterboard box section) , across and into the bathroom pull switch

    Cheers again to all of you for your help

    Shaun
     

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