neutral to earth high voltage

[Simon-0116]

Been to look at a faulty socket on a rcbo and wont hold in, tried to test trip times etc but reading voltage on earth. Supply is tt, 3ph and 1 ph to a domestic property. Shared earth rod. Cant turn house off as belongs to separate person. So tested voltage at 3 ph db, 230, 400 v etc but got 48v n to e.. so i did insulation test on incoming swa, phase to earth, one down to 350 ohms, n to phase, one 459 ohms, n to e grater than 500 ohms. But can work out why 48v n to earth. House looks to have split load rcds, looking through window. My only conclusions is swa supplying house has low insulation. Am i looking in wrong direction. Ive turned power off to barn till i can look at house supply.

 

[Lucien Nunes]

A loose neutral connection would not affect the voltage at the MET with respect to real earth. It would also have caused incorrect voltages L-N and L-L which the OP says were OK at the time when there was excess voltage N-E. So I think that's a red herring.

There was a test result for Zpn (not 'L-N ze' that doesn't make sense!) of 0.4ohms, which is plausible, but the MFT couldn't test Ze. As the installation is TT that suggests the rod is completely hopeless and a small amount of leakage (possibly a perfectly normal amount) from equipment in the house is enough to raise the voltage drastically. Nothing terribly surprising there.

 

[UKMeterman]

We have one of two things going on here;
Either the earth rod is high resistance and thus not working and needs fixing, or there is a L-E fault that is putting AMPS down that earth rod. In both cases there is a fault that needs fixing so the installtion in the first case is properly earthed and in the second case prevent fire and the electricity meter going round like a cathrine wheel!

Go back to the customer and explain that if this leak was gas, would they stop you from fixing it? If the property is rented then they have a duty of care and you may also find suitable phrases in the Electricty at work at.