Voltage Help

[Marky83]

Hello,

Im new to this website and would be grateful of any advice.

Im a fully qualified electrician and got called to an early 1800's property this week to attend a socket that didnt work, well at least thats what i was told over the phone. Infact once i got there, the customer had 3 sockets not working. After a visual inspection and checking the sockets are fully functional i proceeded to test the circuit as they proved to be sound. Now i tested through live-earth and got 240V neutral-earth and got 0V but live-neutral i got 216V to the reason why the RCD trips out once there is a load on it.

There is an upstairs and downstairs ring circuit so i tried the voltage at the fuse board and on the other sockets round the house (including the ones on the same circuit) and all possible outlets and circuits came up L-E 240V N-E 0V and L-N 240V. As you can imagine i have tried everything possible i could think of at the time so if anybody can shed some light on this situation or if anybody has been in a similar situation, i would be very grateful of any help.

P.S I was meant to add in there, the property had a full rewire in 2003

Cheers

Marky83

 

[trev]

Welcome aboard
You're a qualified spark and you can't figure out why a circuit trips when you put a load on it and the only thing you can think of to check is voltage?
Interesting

 

[One_of_them]

get your tester out mate and start with the basics.

also ask if any work has been carried out recently on property, picture hanging, floor laying etc etc

 

[Marky83]

Yes i've tested the circuit and all appears sound and there has been no other work carried out on the circuit or on anything else around it

 

[Marky83]

I have tested it through and everything is sound, sorry i didnt put that in the original quote

 

[trev]

OK lets have all the results test by test mate. There might be something you've missed because you've been at it too long.

 

[plugsandsparks]

Hi, cannot quite make out what you are saying but if you have lost some volts, they must have been taken by a resistance somewhere, best work your way around and take above advice ^^^^^^

 

[Guest111]

if you have 240 l-e but 216 l-n and it trips rcd when you apply a load then there are only a limited number of possibilities,the most obvious being a loss of neutral,there has to have been recent work done or something gone through a cable.

 

[Marky83]

Well this is what i said to the customer however they seem adament they have had no work done. I totally agree with what your saying about a loss of neutral and obviously its just finding it. Cheers

 

[Guest111]

if you did a continuity test on the neutral i think you would find it incomplete,now if you had a break in the neutral at 2 points and one of them was earthed this would cause the problem you describe,as a thought the faulty sockets are not on a radial are they?

 

[bryanh]

Are saying you carried the full ring main dead tests in the correct order and nothing is showing up as being wrong ? as that dont seem right m8? also are these sockets part of the ring or a radial ?

 

[SirKit Breaker]

If this circuit is tested as per GN3 you cant fail to find the problem.

Cheers..........Howard

 

[Plonker 3]

What were the results of the IR test you should have carried out?

Was there continuity on all the RFC conductors?

 

[Deservices]

I'd agree with the loss of neutral could be something as simple as a floor board nail worn though a cable over time. Doesn't sound like a ring to me if you are actually getting a circuit at the fuse board it's probably due to somebody adding a socket where they shouldn't. Just check socket to socket and figure out which cable feeds what shouldn't be to hard to find.