Small voltage from neutral to earth on TT system

[naylorpd]

I'm building a house in Azerbaijan, with 3 phase mains supply and TT earthing. The main transformer is at least 800m from my house. Whilst doing my final measurements before going live, I noticed a small voltage between neutral and earth. It varies between 2-4V and seems to be AC. It isn't a stable voltage, it seems that each time I connect the meter probe the voltage is very slightly different, but so far never above 4V.

It dosn't seem like I can do anything about this, my own earth tested OK after I installed it and the earthing of the neutral line at the transformer is what it is - probably not as good as mine.

In case it's relevant, the incoming 3 phase is on aluminium cable, but once it reaches my property everything is 100% copper.

Do I need to worry about this?

Thanks
Philip

 

[Lucien Nunes]

A small N-E voltage is inevitable in TT or TN-S as there is voltage drop along the neutral cable whenever unbalanced load current is flowing anywhere between you and the substation. Only in TN-C-S will the N & E automatically be at the same voltage at the supply terminals.

 

[Marvo]

^^ As above, if all the other test results are fine then a small N-E potential of a couple of volts isn't a problem.