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Shock Likelihood at Switch.

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Mornin' All,


I have just inspected and tested a renovated  old flat's wiring. The original lighting wiring in places has no circuit protective conductor. The owner has installed metal plate light switches to two positions with wooden back boxes. At these two positions there is no circuit protective conductor. The flat has a new R.C.B.O. consumer unit and all other wiring is good.


I have recommended that the switches have a C.P.C. installed (difficult and disruptive) or be changed to all insulated types.


Just what is the shock risk at these two switch positions? What is the likelihood of the metal plates becoming live due to a fault? Has anyone every seen a metal plate switch break down so that the plates becomes live?


Thanks,


Z.

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  • 0
    Good for you Zoom in sticking to your guns. ESF can only provide guidance on appropriate codes, they obviously did not review your individual situation so are not in a position to exercise engineering skill and judgement on it. However, in arriving at a decision on risk HSE will advise that relevant technical guidance including manufacturers instructions should be taken in to account. The absence of fundamental control measures, irrespective of assessed risk would have led me apply a code 2 or to hold the EICR until the switches were replaced. But that is just my opinion. 

    Interestingly, we failed to get in to the NICEIC on our first attempt 35 years ago because of such a situation. Stupidly we had wired a 2-way lighting circuit without bringing a cpc to the switch. Nice brass accessories were fitted. Everything was going well and we were on schedule for a positive outcome. We were just about to leave the property when the inspecting engineer noticed the switches were brass and decided to do a wander lead check. Deservedly, down the plug hole we went!  Ever since I insisted that we used single core and earth whether needed or not! 

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  • 0
    Good for you Zoom in sticking to your guns. ESF can only provide guidance on appropriate codes, they obviously did not review your individual situation so are not in a position to exercise engineering skill and judgement on it. However, in arriving at a decision on risk HSE will advise that relevant technical guidance including manufacturers instructions should be taken in to account. The absence of fundamental control measures, irrespective of assessed risk would have led me apply a code 2 or to hold the EICR until the switches were replaced. But that is just my opinion. 

    Interestingly, we failed to get in to the NICEIC on our first attempt 35 years ago because of such a situation. Stupidly we had wired a 2-way lighting circuit without bringing a cpc to the switch. Nice brass accessories were fitted. Everything was going well and we were on schedule for a positive outcome. We were just about to leave the property when the inspecting engineer noticed the switches were brass and decided to do a wander lead check. Deservedly, down the plug hole we went!  Ever since I insisted that we used single core and earth whether needed or not! 

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