Live earth fault on every leg of the ring

[T Wilson Elec]

The only possibilities are really
a) cable faulty
b) VERY wacky wiring, e.g. everything connected back to one point somehow
c) MFT suddenly faulty (I guess you have repeated earlier good readings to rule that out already)
Everything else (flood, rats, plasterers, plumbers) wouldn't consistently only affect live.

I'm sure most of us would be interested in the outcome of this one as it's rather a nightmare for you and customer.

Faulty drum is where my heads at

Wiring I did end up belling leg to leg just to figure out how they did it and seems pretty logical doesn’t look like a jb nightmare job like all work looks 10/10 just cheap gear

Megs just been calibrated month or so ago and was in full force last night testing another job and nothing seemed off and while trying to figure out this fault I’ve used some scrap cable to check resistance ect only thing I had to hand

No works been carried out no flooding either there is apparently a mouse roaming around but come on every leg ? Live and earth an all little lad wouldn’t make it past one leg

I will be sure to let you all know if I get to replace it all just waiting on his insurance to see if they will pay me or send there own team

 

[buzzlightyear]

I will be sure to let you all know if I get to replace it all just waiting on his insurance to see if they will pay me or send there own team

all honesty if its a insurance job a team
Would have been their now sorting
Out the problem.

 

[T Wilson Elec]

all honesty if its a insurance job a team
Would have been their now sorting
Out the problem.

The blokes still at work I’ve known him a long time so I was first port of call don’t blame him for going through insurance we all pay the damn stuff might aswell get what we invest

 

[buzzlightyear]

The blokes still at work I’ve known him a long time so I was first port of call don’t blame him for going through insurance we all pay the damn stuff might aswell get what we invest

When I turn up to a job once a customer
Says its a insurance job, me why did you
Ring me up in the beginning. Idiot.

 

[7029 dave]

Reading your comments and others, off scale readings on everything but LE through out the circuit, with every leg stripped down.
If it were damage, damp,water the readings would not be uniform to just LE on every section.
IMO faulty cable drum, it has happed to me, but in my case you could see the physical damage to the cable as it was pulled off the drum.
I for quite some time used to IR test every new drum of cable before installing it.

 

[Petej999]

Sorry I feel I must have worded it poorly but I did mate I took every socket off and every leg between every socket had a LE fault my thinking was the drum must have been
NE >999
LN >999
LE >50

Something like that at install so it would have held fine and now 12 year down line it’s broke down and obviously a shitty LE anyway Would explain every leg having the same fault

Has everything been dissed from the CU are you just testing the wiring or are there any loads still connected??

 

[littlespark]

Very strange that it wasn’t discovered earlier. Bad drums are usually bad from new.

I wouldn’t be quick to assume it’s bad cable because it was a Screwfix board… I get prysmium t&e from Screwfix cheaper than at wholesalers.

So every socket is disconnected fully? You didn’t reconnect as you went round checking legs?

Outside socket?
Hidden joint box?
Squashed up cables in appliance grid switch?

Have you tried ohm setting instead of megaohm?

 

[DPG]

Be interesting if you could pull out a reasonable length of it, maybe an underfloor section, and a) IR test it and b) inspect it

 

[Lucien Nunes]

I think we can stop grilling the OP about faulty or hidden fittings as he repeatedly confirms that the low readings are on every run of cable with bare ends disconnected from the sockets.

The question is now not so much 'is it the cable' as that seems a certainty, but 'how did it get through testing on completion.' Obviously if the PVC mix used for the insulation is partially conductive in its own right, the readings would have been low from new. But perhaps the raw material was not conductive but hygroscopic, and it has absorbed moisture over time that has brought the resistance down from an otherwise acceptable figure when new. Like MI, which will test fine straight off the roll but will drop over time if not sealed.

Although an academic exercise once the remedial work starts, it would be interesting to cut two samples from a length, extract the L core, prove that they measure similarly from core to water when submerged, then keep one submerged for a week but put the other in the airing cupboard and retest both.