Voltage spike causing strange readings?

[MdubElec]

No one likes not know the ending to a saga so here goes.

It turns out it was a lost neutral from the DNO side, which we originally suspected and called the DNO out for. They did earth loop tests on their cables but no dead test continuity, so when we returned in the morning we tested their side and we found the fault between the cut out and the meter.

We had been led down the wrong rabbit hole due to the DNO falsely confirming that the neutral was there, we originally tested our side but decided to test their side after we had called them out once already.

Some damage to a few PIR's, the roller shutter door controls, AC stats and a few other little bits but not as catastrophic as it could have been.

Thanks for the help guys.

 

[MdubElec]

With absolute respect to you fella, your Electrician should be able to understand how to test between phases and phases to earth and phases to neutral to determine if anything is amiss. The DNO supply is without doubt fine, the problem is your end, it is school boy stuff to test between cores, TNS and PME are types of earthing arrangement and nothing to do with a floating neutral which we believe may be the issue.

I didn't explain myself properly, the reason I mentioned the PME was because the DNO engineer did loop readings at the meter to prove the neutral was healthy, but because of the PME he was getting the loop reading from the earth when testing the neutral.

 

[KungFuTurkeyLeg]

Glad to see a happy ending.

A strong sneeze would knacker a PIR, they seem to be sensitive to everything. Small single phase motors rarely survive a 400v blast either, but then neither would I