L- E Fault!!! Help

[DurhamSparky]

Right Chaps

Down Stairs lighting Circuit wired to a 6amp MCB

circuit goes like this

CU - Front Room - Kitchen (9 230v downlights) - Hall - Utility / Outside light - Office....

i know its a L-E fault as the little blighter zapped me on the Earth connection plus my meter reads 0.85 when 500V testing the thing!!

the job is a previous Bodge and so far have uncovered many of faults with the circuit! namely melted connector block and nicked cable's

I spent 4-5 hours on it so far and now its driving me insane!!

when the mcb is made it has a delay in tripping!! and some times stays on for 15 mins before going!! which makes it harder to fathom out!!!

im struggling!! bar telling the customer to rewire the circuit as its a mish mash of mess any sugestions!!

 

[Spudnik]

Steve,

You need to start disconnecting from the furthest point and keep Ir testing until it eventually clears.

That will give you an idea what part of the leg the fault is on.

 

[Andyfm]

Slow tripping faults can often be water getting in somewhere , i`d look at the external wiring first, or at least isolate it then test back from there

 

[odigi]

Steve, have you been through all the test in order of the good book? if so what readings are you getting? Also have you done the tests with all the circuit conductors disconnected from the CB and N and CPC bars?

 

[Sparky Ninja]

Have you tried IR test in the different legs of the circuit?

 

[ringer]

Are you sure there's no sockets or appliances tapped in to this circuit?
How about introducing a fault into the upstairs lighting circuit to check that its mcb works ok, then swapping the MCBs?
Otherwise, yes, convince the customer partial rewire is required. At least you can then recoup some of the lost hours on this fault.

 

[DurhamSparky]

CU to Front Room >200

front Room to Kitchen JB >200

Kitchen to Stairs 0.85 ohms

kitchen 2 way circuit gives me 2.8 m ohms

cant get access to loop on stairs as muppet head spark before has kindly got connections in walls and loft which i cant get to either..!

i never got round to testing utility but outside light is ok >200

Office >200

i left her with front light as its open plan kitchen living area so at least has some light...!!

going back tomorrow to continue!! any body fancy a ride along!!

 

[mnmwill]

I had L-E fault on a lighting circuit the other day, it was just a case of breaking it down and testing each leg individually. Finally found the fault, replaced leg, all good now. If you are only getting 0.85 between the kitchen and the stairs and all other legs test ok , then I would try replacing the cable between these two points.

 

[DurhamSparky]

oh i forgot to mention!!! SHINEY KITCHEN and newly refurbed ceiling with bathroom and tiled floor above!!

kinda pursuaded cust to take out the old ins policy with a well known provider as not got much cash if you know what i mean!!

 

[mnmwill]

Think she best book a plasterer then

 

[DurhamSparky]

i know..!!

the lighhts have been wired horrendous as well..!! used 2 core cable with singles to form 3 core and also used 2 core and chopped a leg out to make 3 core!!

other work is desirable as well i dont really have time to chop cables out of walls and re fix so im happy to pass job on if any bodys interested...!

 

[Des 56]

Is there continuity of the cpc to all of the circuit
If not,there may be a live earth fault not being picked up because, perhaps,the fault is then finding an alternative high resistance route to earth,lower fault current and a little extra time to operate perhaps

The finger zapping may have been a symptom of this possibility or even just induction into the incomplete cpc and you then being the discharge path

How does the song go
Rip it out and start again

 

[Sparky Ninja]

Is there any class1 equipment after the 0.85 reading?

 

[DurhamSparky]

saying that i got zapped by CPC that was attached to back box and not front plate...!! front plate was earthed via 2 way kitchen light cpc and back box was earthed via cpc on 2 way utility light!! im so tempted to say start again on this one as it really is a mess.!!

i still cant find the JB that connects the spots to the light switches!! i know there is one as black red at feed/switch and Blue/Brown at Spots..!! (i can imagine it may resemble a choc block maybe!!)

to keep it simple i may suggest surface mounting cables in less used areas to save money!!

also got 2 landing lights that i could incorporate into the upstairs circuit as stand alone fittings not on 2 way switching to give light to landing and downstairs can be seperate as well...(just means have to turn it off before going up! lol...

 

[DurhamSparky]

Is there any class1 equipment after the 0.85 reading?

pendants all the way mate! apart from outdoor light but that was clear..! and loop in out was in back box so easy to check!

 

[Sparky Ninja]

pendants all the way mate! apart from outdoor light but that was clear..! and loop in out was in back box so easy to check!

Could it be considered an option to remove the cpc from that part of the circuit?
If all accessories are class II after the stage that the L-CPC fault occurs, then you could disconnect the cpc and install a notice at the consumer unit. As long as the client understands the situation, and that they will need to get it rectified in the future???

It's possibly the best option for now.

 

[DurhamSparky]

probably a good option but the boiler comes off in the Utility via a FCU!! but that said this can be removed and a plug top fitted and plugged into ring!!! or i can spur ring off to it...

never thought of that idea mate tbh as im always a one for safety first.....! but it may not work as i re energised the circuit during testing with Earth disconnected from bar and it still popped!! further investigation needed i think..! but like i say last spark was a chimp and botched it all customer even told me he was tempted to kick him form job as he questioned his ability! and i have planted the rewire seed as well ! as that will satisfy my head 100% it would be safe!!

im back at 9am to have another pop at it...!

 

[Sparky Ninja]

Well if it is popping out with the cpc disconnected then these connections need to be located.


If you can't segregate the circuit and leave it working, and can't access the connections then that's it. The legs will have to be redone.


If I was anywhere nearby I'd be there bright an early to help


Best of luck

 

[DurhamSparky]

cheers mate,

i will probably have to conjur a plan to get as much light back as possible!!!

plenty of cables have little niks in them as well so it could be any thing!

might be nice and offer to redo lights for £600 (plus its TT and this side of box is not RCD!!)

 

[blackiel]

Think you been answering your own question from the start,Durham Boy...Total redo...on the grounds of safety and you sleeping properly again,not to mention being called back out,in a perennial fashion,because you were the last one to work on it and you said it was alright,if punter/client questioned original SPARK/Installer,think that says a lot,keep us posted,Mate..

(PS..Get set for world domination,sparking wise)