Day from hell!

[Welsh_sparky_21]

did any of yous ever have days just after you’ve qualified when your doing a simple job but you encounter a slight wee problem and it just snow balls and you’re close to giving up after it’s done lol! Had one a those days

 

[Dartlec]

my day from hell is about to start, old wylex CU with 3871's, back of bottom of corner cupboard in kitchen. all sockets on a 30A, random tripping of MCB. did a few basic tests yesterday without being able to access the CU. Nothing appeared abnormal. testing at a socket L-N and L-E both > 9999 ohms, but L-E and N-E both 0.02 Meg. obviously the IR readings are misleading with circuits still connected in CU. replaced MCB with a 60898 as the original was intermittent resetting even with power isolated, took 3 or 4 presses to get it to stay in,and it was a 2 minute job. cakll last night, still randomly tripping but holds when reset. back today to strip out the cupboard, remove shelf so can access and diss. then some sensible testing.. split ring and track it down. could be simply an intermittent short in a back box (I hope) or maybe rodent damage entailing floors up etc. btw. no RCD on installation. Zs readings all sensible ranging from 0.22 ohms to 0.45 ohms. let you know what i find later.

Sounds like fun. Rodent damage sounds possible, but make sure to check every point before getting any floors up. I had an RCD constantly tripping on Friday that was fine by the time I got there in the evening. Tracked down to an external socket that had lost it's cover and had a small tree pressed against it - so the rain overnight and the wet tree had tripped it all morning, but had dried by the time I got there.....

 

[pc1966]

let you know what i find later.

Yes, interesting to hear once it is done and you are home with a beer or three.

 

[telectrix]

update. worse than anyone can think. opened up old fuseboars (3036, updated with 3871s). 4 x 2.5 T/E enter from rear in a bunch, sheathing not in box, so no way of telling which L,N,E are same cable. pulled lives out of MCB. no r1. pulled assumed N's ..no rN. left r2 for now as no way of telling which is which. both legs of L's read >999K to E, but both read 0.01meg on IR. opened a couple of sockets to split circuit. half the sockets are spurs with hidden JBs under bedroom floors. got 1 leg reads OK, so connects up and 4 sockets working. 5 dead. at this time also pugged in socket tester 3 greens.. OK. then asks the old dear if she's sure nobody been nailing or screwing floorboards ( cables are notched in joists)." my son secured a loose board in my bedroom a few weeks ago". so board up. screw straight through cable. joist charred, adjacent cables blackened. OK, so cut and stripped damaged cable. back at CU, fault clear. joined cable , fault back. split cable again 1 leg good. 1 bad, so leaving the bad leg dissed at the join and at CU, powered up "good" leg. several socket appear to be working, but socket tester shows L-E reversal. also 1 socket only works if the adjacent 15A MCB is on. then the 30A MCB trips. after 5 hours i finally admit defeat and advise a socket rewire and a new CU in an accessible position. obviously some cross connections meaning beds out of house, carpets and floors up. nightmare. thoughs being if this amount of disruption is needed, then rewiring is only option.


1. CU under fixed shelf
2. shorted cablecut and stripped
3. connected in hope.

in 2 and 2, you can see the black scorch marks on the joist.

 

[pc1966]

Oh that is nasty.

 

[nicebutdim]

update. worse than anyone can think. opened up old fuseboars (3036, updated with 3871s). 4 x 2.5 T/E enter from rear in a bunch, sheathing not in box, so no way of telling which L,N,E are same cable. pulled lives out of MCB. no r1. pulled assumed N's ..no rN. left r2 for now as no way of telling which is which. both legs of L's read >999K to E, but both read 0.01meg on IR. opened a couple of sockets to split circuit.

My brain expected to read "beers".

 

[telectrix]

in pic 1. the shelf below the DB is the bottom of the base unit, 6" above floor. above the DB by 6" is the non-removeable shelf, so no room to work. half in, half out the cupboard, and to make it worse, having to use a terminal driver in left hand, so hand blocking off the light from rechargeable work LED light.

them connectors are the dog's danglies. quick connect even if hardly any slack, cover with heatshrink. voila, MF joint.

 

[Dartlec]

update. worse than anyone can think. opened up old fuseboars (3036, updated with 3871s). 4 x 2.5 T/E enter from rear in a bunch, sheathing not in box, so no way of telling which L,N,E are same cable. pulled lives out of MCB. no r1. pulled assumed N's ..no rN. left r2 for now as no way of telling which is which. both legs of L's read >999K to E, but both read 0.01meg on IR. opened a couple of sockets to split circuit. half the sockets are spurs with hidden JBs under bedroom floors. got 1 leg reads OK, so connects up and 4 sockets working. 5 dead. at this time also pugged in socket tester 3 greens.. OK. then asks the old dear if she's sure nobody been nailing or screwing floorboards ( cables are notched in joists)." my son secured a loose board in my bedroom a few weeks ago". so board up. screw straight through cable. joist charred, adjacent cables blackened. OK, so cut and stripped damaged cable. back at CU, fault clear. joined cable , fault back. split cable again 1 leg good. 1 bad, so leaving the bad leg dissed at the join and at CU, powered up "good" leg. several socket appear to be working, but socket tester shows L-E reversal. also 1 socket only works if the adjacent 15A MCB is on. then the 30A MCB trips. after 5 hours i finally admit defeat and advise a socket rewire and a new CU in an accessible position. obviously some cross connections meaning beds out of house, carpets and floors up. nightmare. thoughs being if this amount of disruption is needed, then rewiring is only option.


1. CU under fixed shelf
2. shorted cablecut and stripped
3. connected in hope.

in 2 and 2, you can see the black scorch marks on the joist.

That is a nightmare and I bet there are thousands of houses out there like this, waiting to sneak up on any of us any day now...

Sleep well and don't have nightmares!

 

[telectrix]

what i can't get my head round is the L-E reverse shown on 2 socket testers a chinese import and a fluke, when clearly the L is to L. N is to N and E is to E. the only thing i can think of is that due to the screw in cable, the 1.0mm cpc has been compromised due to repeated fault currents, gone O/C somewhere down the line and confusing the socket testers.

 

[pc1966]

what i can't get my head round is the L-E reverse shown on 2 socket testers a chinese import and a fluke, when clearly the L is to L. N is to N and E is to E. the only thing i can think of is that due to the screw in cable, the 1.0mm cpc has been compromised due to repeated fault currents, gone O/C somewhere down the line and confusing the socket testers.

Or someone has managed to swap L & N in a hidden junction box?

Did you do any other check to see if it was really reversed?

As you say, if and open CPC is floating close to L the socket tester might just think that N is the live one as the "odd one out".

 

[Baddegg]

in pic 1. the shelf below the DB is the bottom of the base unit, 6" above floor. above the DB by 6" is the non-removeable shelf, so no room to work. half in, half out the cupboard, and to make it worse, having to use a terminal driver in left hand, so hand blocking off the light from rechargeable work LED light.

them connectors are the dog's danglies. quick connect even if hardly any slack, cover with heatshrink. voila, MF joint.

That joint is a nice fix tel ??

 

[telectrix]

Or someone has managed to swap L & N in a hidden junction box?

Did you do any other check to see if it was really reversed?

As you say, if and open CPC is floating close to L the socket tester might just think that N is the live one as the "odd one out".

checked at a socket. first, voltstick.. lights up on red (L) no reaction on N or E. then the fluke . 246V L-N. 246V L-E. 40V N-E. thinking cpc is floating due to damage caused by the screw in the cable. as it's only a 1.0mm cpc. however, the leg that showed 0.01 meg L-E was dissed.

 

[David Prosser]

did any of yous ever have days just after you’ve qualified when your doing a simple job but you encounter a slight wee problem and it just snow balls and you’re close to giving up after it’s done lol! Had one a those days

Days from Hell, looking back are the best days you will have!! You will learn more, remember more, understand more and finally get more confidence from them than you ever will from a hundred easy jobs. Suck them up and learn from them. No one ever started a conversation down the pub with an easy job that went according to plan.

 

[123]

what i can't get my head round is the L-E reverse shown on 2 socket testers a chinese import and a fluke, when clearly the L is to L. N is to N and E is to E. the only thing i can think of is that due to the screw in cable, the 1.0mm cpc has been compromised due to repeated fault currents, gone O/C somewhere down the line and confusing the socket testers.

checked at a socket. first, voltstick.. lights up on red (L) no reaction on N or E. then the fluke . 246V L-N. 246V L-E. 40V N-E. thinking cpc is floating due to damage caused by the screw in the cable. as it's only a 1.0mm cpc. however, the leg that showed 0.01 meg L-E was dissed.

Did you test voltage at the connections at sockets that flummoxed the plug in tester?
I've had before plug in tester showing L-E reversal...what happened was the fault blew apart the cpc, which in turn welded itself onto the L from the socket. So at socket L-N 230v, N-E 230v, L-E 0v.

The downside of MCB's and the like, folk will flick them back on until they stay on, damaging god knows what in doing so.

 

[cliffed]

Most of my bad days come from putting things right,especially work that some Subbies who are not actually interested in the job
We all make mistakes,the art of that is to make sure You correct them.

 

[telectrix]

Did you test voltage at the connections at sockets that flummoxed the plug in tester?
I've had before plug in tester showing L-E reversal...what happened was the fault blew apart the cpc, which in turn welded itself onto the L from the socket. So at socket L-N 230v, N-E 230v, L-E 0v.

The downside of MCB's and the like, folk will flick them back on until they stay on, damaging god knows what in doing so.

think it may be something similar, yet, before I'd found the nail in cable i had several sockets powered off the "good" leg, showing correct polarity. (3 greens on the fluke).