Strange voltages

[LlandrilloSpark]

Just wondering if anybody can shine a light on thisI'm working on a 50's bungalow, original wiring, the home owner has basically knocked down a lot of Walls in his house and just stuffed, cut out or taped up various switches, sockets and roses he didn't want.My job along with various other things Is to sort it all out, I'm adding to the existing lighting circuit so I did a EFLI test on 3 roses and 3 switched, all were over 2000 ohms and cpcs are connected in the board and are present at every point.The strange things are whilst 246v exists across L-N the voltage across L-E is about 80, but also what is puzzling me is 20v across N-E, Ze is good and system is TNS , I found all this at 5pm and havnt done IR yet.Cheers

 

[Marvo]

Sounds like a combination of using a digital tester with high input impedance and a floating earth /neutral that's not properly connected/bonded. What type of earthing arrangement does the premises have? I would double check the neutral connection at the CU and test the earth bond.

 

[LlandrilloSpark]

CheersWhat I didn't mention was that when I put my fluke t120 voltage indicator across L-E where the lights would normally shoot up to 230, they hovered at the 75 indicator and the digital readout read 80v, but when I put my Megger MIT across it on the voltage range, it measured 230v!!

 

[yellowvanman]

You're earths aren't earthed!

 

[telectrix]

bad connections on neutrals and /or cpc's. check for oxidation in terminations,
.

 

[daveb_p]

Yes, maybe start with some long lead tests to check your CPC at points along the circuit. - Could be as simple as having caught the CPC sleeving in a termination somewhere maybe?

Dave.