Earth/Neutral fault..Help Needed!!

[dtec dave]

Probably going to get slated for not knowing/doing something wrong but here goes!!

So, been asked to do a board change for a customer, when I turned up they explained that had had a new PME done a few weeks ago, when I mentioned that their house wasn't earthed the customer said that the installers had said it 'wasn't urgent but needed doing at some point' . Anyway I did a quick ZS test on a socket and found I was getting 1.20 ohms..not bad for no earth.

I then proceeded to start dead testing the existing board, upon testing a ring circuit in the house I found that I was getting voltage (190v) between the disconnected neutrals and live. At 1 point I even had the neutral tail disconnected from the meter with the ring neutrals connected on to the neutral block to find all the electrics working in the house!! (To try and explain to the customer what is happening)

Any suggestions on where I begin to start looking for this fault??

Cheers in advance

 

[westward10]

Have you actually verified Ze as suggested in #2. A random test at a socket will prove nothing.

 

[davesparks]

Any good advice to give, you have taken the time to post 3 times on this topic but every post is irrelevant to the question I asked?

The best advice I'd give to start with is that you stop creating dangerous situations by disconnecting the neutral of a live installation.
As lucian has pointed out this will have diverted the load current via the fault to earth and potentially caused a lot of damage in doing so, not to mention the significant danger to your life and that of anyone else in the property.

 

[Simon47]

How does this explain disconnecting the neutral tail coming out of the meter and the board still being live across L-N?

Oh dear. You need to read it again.
You've made no mention of isolating the incoming L so we have to assume that's at around 240V relative to earth and incoming N.
You've disconnected the N.
You measure between the 240V L and something that is now "sort of floating" with various resistive and capacitative paths (one of which is your meter) to both L and E.
So the N will be at some voltage between E and L - and you are measuring the difference between that and L.

 

[Cid]

This thread is making my head hurt. I've read it start to finish and back to front. Still can't work out what the heck is going on

 

[PEG]

Hi dude,i apologise if i have offended you,but your original post title,was regarding the earthing. You were asked several times,including by myself,regarding this,and got no answer.

I am sorry you think my points regarding the safety aspect of disconnecting and then demonstrating,are irrelevant....this is a worry.

I wish you well and success in your quest,but as the great Deborah Meaden said....i'm out?