Neutral earth fault

[PrenticeBoyofDerry]

is this reading between rn and r2 only?
At what level is the cable routed, ground floor, first floor, in void or buried?

 

[Scuttler01]

Yes, between rn r2. Fault is in upstairs adjacent bedrooms. Assuming cable runs under floorboards? Sockets approx 300 mm from floor level.

Thanks

 

[Scuttler01]

Run in plaster but thinking about it it enters and leaves socket 2 at the side rather than the bottom? Would it run in the wall or would you say it should drop down under floor boards?? I'm just thinking out loud!?

 

[JohnW2]

is this reading between rn and r2 only?

I'm not sure I fully understand what you mean by a "reading between rn and r2" (rn and r2 presumably being the resistances of a neutral conductor and a CPC respectively) - do I take it that you mean a resistance measurement between Neutral and CPC?

Kind Regards, John

 

[Scuttler01]

That's what I took it as??

Cheers

 

[JohnW2]

That's what I took it as??

I presume it has to mean that - but it was rather unusual language!

Kind Regards, John

 

[Scuttler01]

So, I'm guessing the best place to start is the middle (socket 2) and try and follow the run to sockets 1 and 3, hoping to find a common fault along the wall. As the cables enter socket 2 in the side rather than bottom, in people's experience, would the cables run buried in the wall parallel to the floor, or just drop down to floor boards and go through that space? Luckily, I've just fitted laminate flooring a few weeks ago. Happy days!

 

[deadshort]

Did you nail the laminate flooring ? ! Beading !!!!!!!

DS

 

[Scuttler01]

No, glued it!! With the rcd being bypassed before I moved in, I suspect it's been faulty for a while...I'm guessing they changed from an old re-wire able fuse board for this new style consumer unit, and the fault was present then...

Thanks

 

[securespark]

Wondering somehow if the sockets are not wired in a standard ring formation and there is a damaged/ wet joint under the floor linking the faulty legs?

A lot of wondering, I know.

Is the spur leg clear in the socket with 3 cables?

 

[Scuttler01]

Yes, spur leg clear...when I disconnected all cores in all sockets, 1 by 1 i shorted live to earth at sockets 1 and 3 to prove these cables went to socket 2 by measuring there. ... It has to be a common fault right?? The only thing I can think is the feed and return cables to socket 2 are running next to each other for a length along the wall and have sustained the same damage, either in the plaster or under the floorboards?

 

[deadshort]

Before you go ripping up the flooring check directly below each suspect socket that there's not a nail in the skirting board which has pierced the cables, logically thats the point that the two cables are physically together in the wall.

If there is a nail or screw you can meter from that to your faulty cable.

Regards,

DS

 

[Scuttler01]

In sockets 1 and 3, the cables enter at the bottom of the socket. In socket 2, thry enter from the side...in normal circumstances, would the cables in socket 2 be expected to leave the socket on the side and either continue straight along the plastered wall, or turn 90 degrees and go to the floor?

Thanks for the nail tip, hadn't thought of skirting board fixings!

 

[deadshort]

If the sockets are far apart it's most likely they go to the floor.


Regards,

DS

 

[JohnW2]

In sockets 1 and 3, the cables enter at the bottom of the socket. In socket 2, thry enter from the side...in normal circumstances, would the cables in socket 2 be expected to leave the socket on the side and either continue straight along the plastered wall, or turn 90 degrees and go to the floor?

That rather depends on whether there is another socket 'to the side' (maybe quite a long way away), which would be the usual reason for cable to exit from the side (and then travel horizontally to the other socket). Otherwise, cables are likely to go downwards and under the floor (or sometimes upwards, if the floor is concrete) in which case the cables usually exit downwards (or upwards).

For a cable to exit at the side and then "turn 90 degrees and go to the floor" would nearly always be non-compliant with current regulations - but that doesn't mean that it's never done!. However, it's so simple/obvious for the cable to go straight downwards if it's heading for the floor, one does have to wonder (which way it is heading) if it goes out of the side of the box.

Kind Regards, John