missing earth

[haj]

Good evening gentlemen upon testing a radial socket circuit on a type b 16 amp mcb i discovered the cpc was open between cu & first socket or what i thought was the first socket the house has been knocked about by various people i think maybe an old socket has been removed or a jb in the wall maybe.I think a new cpc direct from cu to first socket is the best answer as the owner does not want any damage to the new walls that the old t&e goes through, he asked if it was possible to borrow an earth from the other socket circuit as they run side by side on the landing and it has a jb in it not a good idea i said what do you all think ?
cheers

 

[Mac]

If it's been knocked about as much as you say.It sounds like it would be better to re-wire it.How many sockets are on this so called radialHave you tested the ring yet?

 

[AMST09]

Don't take an earth from another circuit...if that circuit is disconnected then your back to square 1

 

[haj]

there are 9 sockets on the circuit and the cpc is ok from first socket onwards.there are only two radial circuits and 1 kitchen ring.
cheers

the kitchen ring is on a seperate cu on its own.

 

[Mac]

there are 9 sockets on the circuit and the cpc is ok from first socket onwards.there are only two radial circuits and 1 kitchen ring.
cheers

the kitchen ring is on a seperate cu on its own.

Definitely wouldn't take an earth off another circuit.Can't you pull a leg from the board to the first socket

 

[haj]

thats the plan i just wanted to know what the views are on borrowed earths ? am going to sneak an earth direct from cu with as little damage as poss may have to take a long route to get there.

 

[Doug]

One option would be to disconnect the radial at the CU and supply it via a fused spur from the ring. This may not be ideal but it could be the only alternative to some more extensive rewiring.

If you are considering replacing the just cpc then is it worth completely replacing the twin & earth to the first socket? If the cpc is damaged or badly joined somewhere then what about the line & neutral? Have you tested them?

 

[Mac]

One option would be to disconnect the radial at the CU and supply it via a fused spur from the ring. This may not be ideal but it could be the only alternative to some more extensive rewiring.

If you are considering replacing the just cpc then is it worth completely replacing the twin & earth to the first socket? If the cpc is damaged or badly joined somewhere then what about the line & neutral? Have you tested them?

There isn't a ring in the property,well there is but it only feeds the kitchen.Rest of the house is fed via 2 radialsForgot to add this,if you spur off a ring,you can only add 2 sockets max

 

[Doug]

When asked about taking the cpc from a nearby socket circuit, I assumed it was from a ring. If, on the other hand, the second circuit is a radial then to come from this circuit instead of from the CU would only be extending the radial. It's perhaps not good practise to split a radial into 2 branches but the regs don't seem to mind (appendix 15, page 363).

P.S. As i understand it, an unfused spur from a ring (2.5 mm T&E, 32A MCB) can only supply one single or double socket outlet. To come from the ring via a 13A fused spur, you can feed as many socket outlets as you like (provided the cable is not too long for voltage drop to become an issue).

 

[haj]

replacing the whole t&e is not poss without damaging the proprerty and customer said no.L&N Are ok so i guess it must be joined out somewhere and the cpc is out..
cheers lots of thoughts as usual.

 

[Matt Thornton]

Is it not possible to disconnect the existing feed to this circuit & refeed it somewhere else along the circuit?, that way you may find a route that does not damage the building fabric, or if it'san upstairs circuit a JB. Cheers, Matt