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PE advice by Napit (hot tubs)

ebee

There is an article in PE and I have just received it via email.

I am disappointed that the article seems to suggest that it contains all you need to know yet no mention is made of earthing systems

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    John Peckham: 
     

    Evening All

    You may find this article in IET Wiring Matters more useful.  

    https://electrical.theiet.org/wiring-matters/years/2021/86-july-2021/hot-tubs/

    It does cover PME earthing.

    If you register with the IET to receive Wiring Matters it will come to you via an email.

    JP

    If we're worried about perceived electric shocks - where it sounds like having an earthing system even a few volts above true Earth could be a problem - then is a TT system really any better than PME? On a TT system earth leakage currents (either from filters etc or just damp getting into things) will raise the voltage on the Earthing system (Ohm's Law - leakage current x Ra) - say 50mA and 200 Ohms would produce 10V - and for indefinite lengths of time.  BS 7671 only require we keep it below 50V.

       - Andy.

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  • 0

    John Peckham: 
     

    Evening All

    You may find this article in IET Wiring Matters more useful.  

    https://electrical.theiet.org/wiring-matters/years/2021/86-july-2021/hot-tubs/

    It does cover PME earthing.

    If you register with the IET to receive Wiring Matters it will come to you via an email.

    JP

    If we're worried about perceived electric shocks - where it sounds like having an earthing system even a few volts above true Earth could be a problem - then is a TT system really any better than PME? On a TT system earth leakage currents (either from filters etc or just damp getting into things) will raise the voltage on the Earthing system (Ohm's Law - leakage current x Ra) - say 50mA and 200 Ohms would produce 10V - and for indefinite lengths of time.  BS 7671 only require we keep it below 50V.

       - Andy.

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