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Neighbours appear to have gone away for the weekend, so been unable to offer Zs test at pod.
I, m progressive leaning towards the possibility there is actually nothing wrong and you could end up trying to fix something that is, nt broken.
The DNO found nothing wrong with the supply or the earthing.
They isolated the problem to the ring.
The issue was solved when the loose earth was reconnected.
Where does that leave us?
Neither the homeowner nor yourself mentioned that any appliances had stopped working,which confirms the integrity of Land N and rules out one of my previous suggestions about the earth been used as a, return wire.
That brings us back to intentional earth leakage from one (or more) of the appliances.The circuit for this current has now been opened, creating a "broken neutral" type scenario. This voltage will appear on all class 1 appliances and metalwork connected to them on the affected part of the circuit.
The above is easily established by plugging out all appliances and isolating all fixing appliances on the ring. Disconnect the earth that caused the initial problem. Test at the tap and it should be volt free. Plug the appliances back in progressively, testing as you go and you should find the 120 volts reappearing on the tap.
I have experienced the above problem on several occasions