Earthing at transformer

[SimpleSimon]

Has anyone ever seen a supply neutral from the transformer that isn't earthed along the length of it?
Reason I ask is because finishing a TT install today, was getting about 100V between live and earth and about 70V between neutral and earth (237V between live and neutral) but my earth rod is fine and back at the start of my SWA in the board room. So I'm thinking broken neutral?
Any suggestions throw them at me because I didn't have any time to investigate, just powered it down and left thinking.

 

[Knobhead]

Simon, what voltages are you getting at the board? Is this an O/H supply? Just asking to get some idea which way to turn.

 

[pirhead]

Just popped into my head frm somwhere doesnt the regs talk about voltages to earth in a tt not being greater than 50V:shocked3:

 

[jumpin jax]

hi, sounds like a L-E fault on the installation, IR test your cable and if origin is TT test the incoming RCD, if the origin is TNCS check Ze at origin and to true earth

 

[SimpleSimon]

Simon, what voltages are you getting at the board? Is this an O/H supply? Just asking to get some idea which way to turn.

By O/H do u mean old house?if so no it's a new supply but it's fed from a very old school hence why I didn't export the earth as I didn't entirely trust it.
Yes Jax sounds like an L/E fault, maybe a fault on the supply cable. I'll IR test it when I go back.

 

[Knobhead]

O/H = overhead :blush5:

 

[SimpleSimon]

Woops.  no it's a transformer about 50 meters away.

 

[Knobhead]

Right now that’s out of the way what are the voltages L>E N>E L>N.
E being your earth rod.

I’ll tell you now I’ve got my suspicions as to what it is, but I need the readings. And if it is what I think you’re going on a nature ramble!

MOST important is it a 3-phase local transformer? If it is this could affect other consumers.

 

[SimpleSimon]

Do you know what happened Tony?!! Stupid plumber disconnected the conductor and buried it back in the ground without telling me. Stupid stupid stupid &@&£###
But I'm curious to know what your theory is/was?

 

[Engineer54]

Why would a plumber be disconnecting a cable, ...Any cables??

 

[SimpleSimon]

I don't know Engineer. It wasn't even in his way. I popped by today, poked my head around the back to find a tap has magically appeared.
Once connected I got a Ze of 0.45 ohms and a Zs of 33 on my sockets. 

 

[Knobhead]

If it was an O/H supply a floating neutral at the supply, but I’m wrong so I’ll go and hide in the corner

 

[SimpleSimon]

If it was an O/H supply a floating neutral at the supply, but I’m wrong so I’ll go and hide in the corner

Tony that was my first thought too. :cheesy: great minds think alike.