Neutral/Earth Fault

[Reload]

Does anyone have experience of neutral/earth faults and how you found it?

 

[tronic]

Hi, i am experianced at finding faults so may be able to help with some more info, earthing arrangement problem etc.

 

[sparkyork]

are you talking wiring faults or installations with appliances causing faults etc.

if to do with wiring you often find a neatral in a metal box been caught by a screw or something, and at ceiling roses a screw that caught the lampholder neutral connection on the 2nd fix stage, lots of posibilities, chase that fault with a megger!! i love fault finding find it much more interesting than the other mondane electrics!

 

[spark-doctor]

This has the possibility of turning into a very long thread.

 

[sparkyork]

yeah its got potential to earth hasnt it!!

 

[tony.towa]

If it does end up a very long thread it's your own fault!!

 

[Shakey]

Does anyone have experience of neutral/earth faults and how you found it?

Have you isolated which circuit has the neutral to earth fault yet, thats the starting point.

split each neutral in turn from the neutral bar and IR test it to the earth bar.

Once you have found the circuit, walk to the middle of the circuit (or where you think it is) Split the neutral (lets say its a a ceiling rose) and IR test each one to earth. You find the half of the circuit the fault is in, then just keep splitting down. This is the 'split half' tecnique, i have used it extensively with large machine control circuits

 

[Spudmiester]

The spit method is about he best way, anything else is hit and miss guesswork !

 

[Kensprint]

It is the only reliable method for accurate fault finding.

 

[wayne]

when testing ;IR test would show up a nuetral to earth fault

 

[Reload]

Great thanks everyone - I will investigate as you [all] described. The circuit is a radial socket cct (not installed by myself). I noticed that one of the socket circuits was not on the RCD side of the board - I tried it in the RCD side and, probably, found why the person who changed the consumer (apparently 3 years ago) had not included this cct on the RCD side; the RCD kept tripping. So, I had a look in all the sockets (metal clad 2G type) but could not find anything obvious so I guess the fault must lie within the interconnections or from the board to the first socket (of course its all hidden underfloors, walls etc along with any JBs). With this type of issue what are the possible consequences, live metalwork; MCBs not tripping in the specified times; nuisance tripping; fire hazard?

Thanks

 

[sparkyork]

its also not unheard of for sockets to be faulty either, give them an ins res test as well

 

[Reload]

OK will do - yes you are right I shouldnt assume anything......

 

[wattsup]

It's not bound to be a fault, any equipment plugged in may be neutral earthed anyhow, transformers on ch systems, some elv lighting systems, door bell spur off ring circuit, door entry, cctv, elv fans in bathrooms, burglar alarm.. loads of external stuff will seem earth neutral fault, old trannies trip rcd's -

 

[Shakey]

It's not bound to be a fault, any equipment plugged in may be neutral earthed anyhow, transformers on ch systems, some elv lighting systems, door bell spur off ring circuit, door entry, cctv, elv fans in bathrooms, burglar alarm.. loads of external stuff will seem earth neutral fault, old trannies trip rcd's -

what if they are not full trannies and just like the occasional bit of cross dressing?

sorry, couldnt resist it!