strange voltage

[sunsno]

Just been doing some pre work testing on a ceiling rose.
The meter refused to do the Zs test. After further investigation it seemed that there was around 140V between Neutral & Earth. I double checked with another meter, same thing. They are both calibrated Part P approved meters not cheap ones.
Could this be due to a borrowed Neutral? But why 140V.
Can any of you, more experienced than I, give any clues.
Help much apreciated.

 

[Spark123]

Could easily be due to a problem with the CPC, if you do an R1+R2 check what do you get? What is the Ze?

 

[RF Lighting]

Yep, sounds to me like a CPC not connected to earth.

 

[Taylortwocities]

Or do R2 using long lead method

 

[sunsno]

Go to the top of the class guys.

Both R1+R2 & R2 long lead show > 200. The CPC is physically connected in the CU so obviously a break somewhere else in the circuit.

Why is it always the quick favor for a friend that turns into one of these?

I should have checked for this at the time but that 140V had me looking for more complicated problems.

I'm still not sure how you get 140V across two conductors one of which (cpc in this case) is not connected. Can you induce that much? Help me out with the maths.

At least because its a TT system (Ze 13) everything is on an RCD but it still ain't good.

Thanks very much all.

 

[Spark123]

The displayed voltage is to do with the high impedance of your measuring device and the amount of current which can flow, probably only a few micro amps.