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An interesting issue with a TT supply

Alan Capon
An interesting real life example of why you need double pole switching with a TT supply. The scenario is a small village with a few customers supplied by a single pole mounted transformer. 


We got a call from an electrician working in a property who had measured 400V phase to earth, 210V neutral to earth, and 241V phase to neutral, and was understandably worried. Any suggestions of what I tracked the fault down as? This can happen on any TT supply, but is fortunately very rare - I have come across it three times in 20 years. 


Regards,


Alan.
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    Are we allowed to know why the electrician had been called in - had things stopped working, had the householder experienced a shock? Did any of the other villagers have a problem?


    L-N is normal. L and N appear to have floated up more or less together, so as BOD suggests, perhaps the transformer is no longer grounded?


    Could there be a problem on the HV side? (Just guessing now!)
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  • 0
    Are we allowed to know why the electrician had been called in - had things stopped working, had the householder experienced a shock? Did any of the other villagers have a problem?


    L-N is normal. L and N appear to have floated up more or less together, so as BOD suggests, perhaps the transformer is no longer grounded?


    Could there be a problem on the HV side? (Just guessing now!)
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