Neutral fault

[Sb8389]

Hi guys,
been to a fault today where customer is saying they have no power to 6 sockets but all other points ok (all power on one ring main)
when I arrived I checked for power with my martindale and got a L-E reverse symbol at the six points. I then checked voltage at the sockets and got 230v L-E and N-E but nothing L-N. So I thought I must have a neutral fault somewhere.
i then checked ring continuity and found the neutral open circuit. Why would it show voltage across my neutral to earth when all loads have being disconnected. I have checked all sockets and cannot find a loose connection. Any advice on where to go next. If you have any questions where I have not made myself clear just ask. Thanks

 

[Guest77]

any plumbing been done recently? i ask because the other week i had the same fault. the wet-pants had put his circular saw through a 2.5mm. cut clean through the neutral. sod must have known he'd done it as his saw would have stopped. bugger fitted his pipes, nailed the boards back, said nowt. lucky i was in a good mood that day or i'd have nailed his pipes.

Is geordie back on his feet? :biggrin:

 

[telectrix]

Cut the nonsence regarding continuity checks and whack 500 volts between all cores as you were trained on site and at tech when you did your apprenticeship, it is the only way to check all is okay, 1000 even, any problems will show straight up.

how will an IR test show a broken conductor?

 

[Deleted member 9648]

If it's a ring then all the sockets will have voltage regardless of a break in the rn. You need to check whether you have correct r1 and r2 to verify the circuit is actually wired as a ring,it sounds like it isnt. If r1 and r2 are good then that would suggest more than one break in rn.

 

[Guest77]

how will an IR test show a broken conductor?

meggar between the neutrals at the board, if there is a break in the ring it will show up, if there is a short between neutral and earth it will show up, I would meggar the cores and then do a r1+r2 as well afterwards, anytime there is a fault on a power circuit I would meggar all the cores to see if any breaks or shorts evident.

 

[Sb8389]

Should have said that I did an IR test and it showed 0.02 meg across one leg of neutral-E (no RCD fitted,no PME just some more info I missed sorry guys)everything else tested ok so I know there is a problem,I will start breaking circuit down tomorrow. No plumbing being done or DIY work.

 

[Guest77]

Should have said that I did an IR test and it showed 0.02 meg across one leg of neutral-E (no RCD fitted,no PME just some more info I missed sorry guys)everything else tested ok so I know there is a problem,I will start breaking circuit down tomorrow. No plumbing being done or DIY work.

Fair enough mate, I would have also done the same test.

 

[Deleted member 9648]

meggar between the neutrals at the board, if there is a break in the ring it will show up, if there is a short between neutral and earth it will show up, I would meggar the cores and then do a r1+r2 as well afterwards, anytime there is a fault on a power circuit I would meggar all the cores to see if any breaks or shorts evident.

Buggar that,do an insulation test instead.

 

[Sb8389]

It is wired as a ring wirepuller as I tested r1 and r2 so I think ur right there will be probably be more than one break.

 

[telectrix]

it's a 4 finger kitkat then?