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What earthing arrangement is this?
Former Community Member
The supply is from a private transformer in a four core cable 3ph + n. The cable armour is earthed and connected to the MET. However there is also a green and yellow cable connected to the neutral terminal at the main isolator going back to a the transformer casing. The transformer is only 5 or 6 metres away. I think this must have been intended to make it a tncs supply but seems to me to just create parallel neutral conductors. Or is it tn-s-c-s? I have only been able to go off visual inspection because I could not disconnect the supply..
In the original post it's said that there is a cable between the LV neutral and the transformer case surely this is wrong as the LV. Neutral will be raised to some high voltage in the event of an a HV flashover as unlikely as that is is it allowed to have that link? I thought the two sides should be kept seperate
In the original post it's said that there is a cable between the LV neutral and the transformer case surely this is wrong as the LV. Neutral will be raised to some high voltage in the event of an a HV flashover as unlikely as that is is it allowed to have that link? I thought the two sides should be kept seperate
