Neutral Earth Fault

[uksparks]

Hi,

ok ok so I tested this old 3036 board a week ago ready to change today, all ok, nothing bad.

went today to change the board, changed it all etc, had to extend two legs, but other than that, nice job.

i go to switch it on prior to testing like you do, and one of the RCDs won't hold.

bugger, what have I done? Scratching head...

tested IR and its 0.02 between neutral and earth, so I think maybe I missed something previously, I quickly removed a few faceplates as there were only 6 sockets on that ring as it happend, nothing obvious.

anyway, so I think I'll try continuity between Earth and neutral at one we of the ring and got 0.61 and did it the other end and it was 0.02, so I think, that's a bit sodding close to the board, what could it be?

so I start t remove that circuit from the board thinking maybe of done something strange with a joint where I'd extended the leg... Nothing.

so I stand back and think what the heck is it, then I think hang on those shelves weren't there before.... Three large oak shelves, in the return on the wall directly sbove the fuse box....

i thought, I wonder... So got the meter out and touched it on a screw head on the bottom shelf and would you sodding believe it I had continuity!!!

anyway, so I removed the screw and it resolved my problem...

Customer later returns home, says everything ok? I said yes, it is now...

i said they are nice shelves, did you fit them? No we had someone do it for us.... I said tell them they drilled through a cable.

thete were probably 8 cables going straight up the wall where he had drilled 3 holes so not sure how he managed to miss the others, luck I say!

anyway...

 

[R G]

So whats to be done with the cable then ?..

 

[davesparks]

I may have misread that but I couldn't see the bit where you removed the damaged cable and replaced it. You obviously didn't leave a damaged cable in the wall, imagine the poor sod putting wet filler in the hole and getting a shock!

 

[Deleted member 72666]

Good lad, well done!

 

[Leesparkykent]

Did you repair the cable?

 

[Deleted member 72666]

Did you repair the cable?

I assumed he had! He's got to have surely?

 

[uksparks]

Changing the board was the first part of many other jobs I'm doing there over the next week, so will replace the damaged section this week at some point, they want quite a lot of other bits done and this just adds to the list.

 

[Marvo]

..........i go to switch it on prior to testing like you do........

Hmmm, definitely not like I do.

 

[Pete999]

Can't leave that cable in there without repairing it, must have missed that bit when you said you repaired it.

 

[davesparks]

Oh well that's allright, you've isolated the damaged cable until it's repaired then?
It's not just a damaged cable sitting in the wall, with a partially cut live core getting nice and hot as current goes through it, or frayed bits of damaged copper waiting to make contact as soon as someone slams a door and the wall vibrates.

 

[uksparks]

Hmmm, definitely not like I do.

I only changed the board, why shouldn't I just turn it back on? I didn't change anything with the installation.

 

[Pete999]

You did what

 

[Leesparkykent]

I only changed the board, why shouldn't I just turn it back on? I didn't change anything with the installation.

......

 

[uksparks]

You cannot tell me you test fully every circuit prior to energising every single time? The whole lot got tested. Don't sound so surprised!

 

[R G]

To change the board you have to test first surely , there could be any fault imaginable even if it was in service before, this would have given rise to the damaged cable before attempting to liven it up...

 

[Pete999]

You cannot tell me you test fully every circuit prior to energising every single time? The whole lot got tested. Don't sound so surprised!

Well actually yes I would test afterwards, why was the board deemed for a change in the first place?

 

[Leesparkykent]

You cannot tell me you test fully every circuit prior to energising every single time? The whole lot got tested. Don't sound so surprised!

Why wouldn't I do all my dead testing before energising?

 

[davesparks]

You cannot tell me you test fully every circuit prior to energising every single time? The whole lot got tested. Don't sound so surprised!

When replacing a DB yes, but I carry out the tests as I am fitting it. Helps to make sure I haven't made any mistakes in the labelling/identifying of rings

 

[uksparks]

Oh well that's allright, you've isolated the damaged cable until it's repaired then?
It's not just a damaged cable sitting in the wall, with a partially cut live core getting nice and hot as current goes through it, or frayed bits of damaged copper waiting to make contact as soon as someone slams a door and the wall vibrates.

Can't leave that cable in there without repairing it, must have missed that bit when you said you repaired it.

It will be replaced tomorrow or Thursday.... I'm not going to leave it! Jeeees calm down, what do you take me for!

 

[Pete999]

It will be replaced tomorrow or Thursday.... I'm not going to leave it! Jeeees calm down, what do you take me for!

So in the mean time it could catch fire or worse still kill someone, if you couldn't repair it righr away then imo you should have isolated the dodgy circuit until the repair has been done.