Short Circuit Between Earth & Neutral

LWC

Joined
29 Nov 2004
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Whilst installing a new ring main in our converted garage I noticed that there was a short circuit between the earth and the neutral. Thinking that I had done something wrong I traced the short back to the CU. It was nothing to do with the wiring that I had added but and the fault(?) already existed.

I have searched many forums on information about this problem and I am confused. Should there be a short circuit between the neutral and the earth or do I have a problem that needs resolving?

Please can someone help as I really do not know if there is a genuine problem or not.
 
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The "short-circuit" is probably the earth neutral link on a PME/TN-C-S incoming supply, where the earth and neutral are combined inside the service fuse block, to give a good earthing facility of low "loop impedance".

Try turning off the mainswitch, and measuring the neutral earth resistance (it should be open circuit), and then turn on the mainswitch, but ensure fuses are out or breakers off, and measure again, it should be very low, perhaps 0.05 of an ohm at the fusebox.
 
Do you know what kind of earthing arrangement you have?

TN-S or TN-C-S for example.

In TN-C-S Earth and Neutral are combined and are at the same potential.
In TN-S the earth uses the REC's supply cable sheath back to the star point.
 

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