Strange fault, can’t work it out

[DPG]

Tenner says it's a bad neutral connection in the tee off joint under the pavement.

 

[DPG]

What did they find?

 

[Lucien Nunes]

Tenner says it's a bad neutral connection in the tee off joint under the pavement.

I don't think there's any evidence it's a CNE fault, I would expect it to be the line connection that is high-resistance. The EFLI will be bad, the voltage will vary, but there won't be any other symptoms like tingles off things.

But what was overlooked early on, is that any bad connection with enough resistance to affect things this badly, when loaded with heating appliances, will get pretty hot itself. If nothing upstream of the DB busbars was evidently toasty, then there would have been little doubt that that it was the DNO's problem even before getting the voltmeter out.

 

[DPG]

I can see your point there Lucien - there would be tingles felt if the neutral had a high resistance joint. Although if all accessories are plastic then this may be masked.

 

[Lucien Nunes]

Or, of course, that the equipotential zone is very effective and everything in the house is riding nicely on the faulty CNE. IIRC there was a thread on here with an open MEN in the street, where the only symptom was steam from the soil around a metallic water service that was shouldering the load of a few properties.

 

[DPG]

I've seen two failed neutral connections in tee joints under pavements. One was feeding my own property, and both were installed in the 1970s. DNO came out quickly to sort mine - piggy backed from next door neighbour''s meter cupboard with a temporary bit of concentric until the joint was fixed.