Fault finding

[Paul.1980]

Good afternoon all, hoping some might be able to explain a strange fault I am having. After installing a new ring mains I couldn't get the circuit live because of an earth fault. I split the ring and found live earth tails on both ends of the ring. My initial suspicion was a screw through both tails some where, but then I found the fault on the able running between sockets and thought it highly unlikely to have three screw through 3 separate cables. Without a my multi meter I had to get creative so connected a redundant cable just to the live in the socket and found the same fault. With just a live feed both earth and neutral became live. Can anyone shed any light on this? Is it back EMF?, some kind of magnetic fault? How can three different lengths of twin and earth all have the same fault? 

 

[Sharpend]

Who installed it? Are they qualified? 
what tests have been carried out on the cables? 
don’t put any redundant or other cables onto a known faulty circuit -both dangerous and stupid. 
 

is the cable accessible or buried? 

 

[Murdoch]

I think you need a competent spark .......

 

[ProDave]

Yes sorry to say you are neither competent or have the right test equipment to test and fault find this.

TIP: you sort this out with DEAD testing before you energise it. You will need an insulation and continuity tester as a minimum.

 

[Geoff1946]

I'm confused by what you have done and what you have measured. 

If you are checking which conductors are "live" with either a high impedance multimeter, (intended for working on electronics) or (guessing) with the infamous neon screwdriver, then you are fooling yourself.

If any one wire in a multi core cable is actually connected to mains supply any other wire connected to nothing at all, will light a neon or show voltage on a high impedance meter. It's called capacitive coupling.

 

[kerching]

My money...

self install

no dead test

lidl multimeter

neon

:coffee opcorn

 

[SPECIAL LOCATION]

Good afternoon all, hoping some might be able to explain a strange fault I am having. After installing a new ring mains I couldn't get the circuit live because of an earth fault. I split the ring and found live earth tails on both ends of the ring. My initial suspicion was a screw through both tails some where, but then I found the fault on the able running between sockets and thought it highly unlikely to have three screw through 3 separate cables. Without a my multi meter I had to get creative so connected a redundant cable just to the live in the socket and found the same fault. With just a live feed both earth and neutral became live. Can anyone shed any light on this? Is it back EMF?, some kind of magnetic fault? How can three different lengths of twin and earth all have the same fault? 

Yes to explain it simply...

If the correct design, install, test & then energise procedures, as given in BS7671 wiring regulations, had been followed..

Then it would be impossible to have the symptoms you describe..

The old saying "A little knowledge is a dangerous thing" is very, very, very true when it comes to electrical alterations.

It sounds to me like you have the classic mix of incompetence, stabbing in the dark, guessing what to do, while using incorrect tools and test gear.

You need to strip it back to basic and start back at the correct test procedures given in BS7671 to identify exactly what your problem is.

Ring continuity & Insulation resistance tests will probably be your friends on this diagnosis..

If you do not understand what they are, or have a suitable calibrated test meter,

or know how to do them, then you need to employ someone who does.

Also.. Installing new circuits is also notifiable under part-p building regs,

so will need correct testing and certifying in order to obtain your building regs compliance certificate for your new ring circuits.

     Guinness