Oh the irony: the annoying irony

[ToughButterCup]

Being a responsible builder, I installed our eyewash station in the most used room of the house - the kitchen. Right where everyone can grab it easily and quickly.

 

Put it up, right pleased with myself, until Debbie asked why the kitchen lights weren't working anymore?

I've put a screw right through a cable buried in the wall haven't I?

Right here.....

The right hand screw is the culprit. The mood-o-meter  says it all.

 

To repair it, I need to

• isolate the circuit, prove that it is is dead ( a la John Ward)
• Dig the cable out, and find the break

 

Then  what?

Help please....... I know less than anyone in the world  about electrics.

Thanks

Ian

 

 

[Construction Channel]

hope you only hit one core, get the tape out and cover it all back up quick.

 

if you hit more than one core then technically I suppose you will need to somehow lose a junction box in the wall or get some crimp connectors (if that's still acceptable)

 

probably best to wait for someone that actually know what they are doing

[SteamyTea]

As this is the house they is going to be knocked down oneday, just do a temporary fix with a bit of tape.  You could solder a bit of copper in if needed.

Make sure the earth is good.

 

Is the light switch above or below the damage.  If it is not, don't trust the rest of the house wiring.

[Onoff]

ISOLATE THE POWER!!!

 

...before you do anything. Potentially, touching that screw you could get a lethal belt. 

 

You need to expose the cable which will mean digging it out to expose. Crimping is fine. I have some idiots guide pictures to doing a proper job somewhere. 

 

 

[Jeremy Harris]

First off, get a cable/stud/pipe detector and get into the habit of using it all the time............................. (I know, too late, bolting stable doors etc)

 

Technically you're not allowed to put junction boxes inside plastered walls, with the exception that a crimped and sleeved joint is allowable, as is a soldered and sleeved joint.  I once repaired a fault like this by managing to cut a small hole, pull enough slack out to strip and join the damaged wires (only because the cable was inside an oval conduit, and there was a bit of slack in the roof space above) and then solder and double heat shrink sleeve the repair, adding a small bit of galvanised steel cable channel over the top of the repair before filling, sanding and repainting the wall.

 

 

Repairs like bits of chocolate block, twisting wires together and wrapping with insulation tape, fitting a buried junction box etc are all verboten, and shouldn't be contemplated, tempting as it may be.  Inline crimp joints are the easiest to use, but need added sleeving in my view.  The crimped repair also needs adequate protection, and a short length of galvanised steel cable channel works well, as it can be bonded into the hole over the cable repair and then makes it easier to fill the hole without the risk of getting wet plaster into the cable joints (one reason I like the idea of adding a secondary heat shrink sleeves over the crimps in a repair like this - it seals the joints as well as adding an additional layer of insulation).

 

 

Edited October 21, 2017 by JSHarris

[Jeremy Harris]

2 minutes ago, Onoff said:

ISOLATE THE POWER!!!

 

...before you do anything. Potentially, touching that screw you could get a lethal belt. 

 

You need to expose the cable which will mean digging it out to expose. Crimping is fine. I have some idiots guide pictures to doing a proper job somewhere. 

 

 

 

 

Was this the idiots guide: http://wiki.diyfaq.org.uk/index.php/Cable_crimping ?

 

Looks pretty reasonable, with lots of pictures.

[Onoff]

1 minute ago, JSHarris said:

 

 

Was this the idiots guide: http://wiki.diyfaq.org.uk/index.php/Cable_crimping ?

 

Looks pretty reasonable, with lots of pictures.

 

No, not mine but clearly from the same school of thought! Only difference is I used heat shrink crimps to g'tee no moisture is ever getting in that crimp!

 

Ordinary crimps are fine though.

[Jeremy Harris]

I like heat shrink crimps, but I inherited a large box of assorted crimps years ago, and none are the heat shrink ones, but my fix has been to just add a bit of adhesive heat shrink over each crimp.

 

I did pretty much exactly what Ian has done around 20 years ago, when replacing some wall lights.  I made the cardinal sin of assuming that the wiring to the socket underneath and about a foot or so to the right of the wall light would run vertically up the wall.  It didn't.  Some cowboy had run the cable diagonally across the wall.  What's worse is that after I'd chiselled out a hole to repair the cable, I found that one of the screws for the old wall lights that I'd replaced had nicked the cable, and had luckily only hit the neutral.  It had been like that for years, since the extension was built I'd guess.  It was just my stupidity in not checking that led to me running a hammer drill bit right through the cable, as the new wall light screw centres were different to the old ones.  The daft thing is that I'd turned off the lighting power and checked that it was dead, but the cable I hit was the ring final for the sockets.

[SteamyTea]

I hit the cooker cable once (similar problem, cable was in an odd place). Made quite a bang.

Also did a 100A fuse at work, that made a larger bang

[MikeSharp01]

1 hour ago, recoveringacademic said:

Put it up, right pleased with myself, until Debbie asked why the kitchen lights weren't working anymore?

I've put a screw right through a cable buried in the wall haven't I?

Right here.....

ISOLATE THE POWER, then just check that you have hit a cable and that the lights are not out for some other reason, from the picture it looks like an odd place for cable to be running, is the light switch above / below it, directly to left or right of it? (In which case nuff said) IIRC you put up the eyewash station a long time ago or talked about it at least.

[Onoff]

This was to demo joining two bits of T&E,  2.5mm new & old in this case,  (note the cpc  (earth) might be smaller):

 

Dead easy on a bench, fiddly in a wall, even getting the crimping tool in of course:

 

Strip the sheaths:

 

 

Stagger the joints so you don't get the "python after a large meal" bulge in the middle. The join needs to be long enough so you can slip the heatshrink on and slide along far enough to do the crimping and ideally shrink the crimp without affecting the tubular head shrink:

 

 

 

Strip the ends:

 

 

 

Heatshrink slipped on BEFORE you crimp!

 

 

 

 

Crimp heat shrunk - has glue in that melts and sticks to the core:

 

 

Green / yellow sleeving on. SOMETIMES as said above you might want a smaller crimp for the cpc:

 

 

Cpc done:

 

 

All neatly crimped, old colours for the heatshrink 'cos I've got it:

 

 

Heatshrink over the top:

 

 

Chuck it in the wall and get plastering!

 

 

Similarly it could be soldered but make damn sure you get no sharp wispy bits of solder that might poke through the heatshrink!

[Jeremy Harris]

I did solder then heat shrink sleeve the cable I drilled through, but only because I didn't have enough room to fit crimps easily.  I'd not recommend it unless you're a dab hand with a soldering iron in tight spaces, as it was far from easy to do.  It probably took three times longer than using crimps, too.  I was just reluctant to make a bigger hole in the wall, so was trying to do it with the wires pulled out as far as I could get them and sort of bent around in a loop to meet each other.

 

TBH, I think I'd have been better off just making a bigger hole in the wall...................

[ToughButterCup]

Blimey lads!

I write a post,  go for a blow on Arnside Knott overlooking Morecambe Bay - hang on like grim death  to my wig - and come back to all of this. Thanks very much.

 

Least I can do  now is to make a pucca job of the repair. Having isolated the circuit first

[ToughButterCup]

2 hours ago, MikeSharp01 said:

[...]

IIRC you put up the eyewash station a long time ago or talked about it at least.

 

It's been on the bottom of a long list for a long time.

[Nickfromwales]

3 hours ago, recoveringacademic said:

 

It's been on the bottom of a long list for a long time.

Now to see if, between now and the end of the build, anyone gets anything in their eye

A 4-pack says they don't  

[Onoff]

.You could.....rip it out of the wall, repair and whack it in a length of surface trunking "just for now". Or, depending where the switch is now, move it up above the damage.

 

I've actually lowered one light switch to 1200 via crimping a new bit of T&E on.

[ToughButterCup]

3 hours ago, Nickfromwales said:

Now to see if, between now and the end of the build, anyone gets anything in their eye

A 4-pack says they don't  

You've lost that one. Durisol is dusty. And covered in cementitious material. Lots of chasing out to do. I now never go into the house without eye protection. 

 

That'll be a four pack of Hogoblin please. 

[Lesgrandepotato]

Well you’re never going to win that one with goggles on. 

[Nickfromwales]

55 minutes ago, recoveringacademic said:

You've lost that one. Durisol is dusty. And covered in cementitious material. Lots of chasing out to do. I now never go into the house without eye protection. 

 

That'll be a four pack of Hogoblin please. 

Shitzen! 

[ToughButterCup]

Rivalling @Onoff's capacity for procrastination, I'm getting round to mending this today...

 

This is what I found

 

Nice one, Ian.

 

Hmmm, stripping it out further, I got to this...

 

 

Taking it one step further......

 

 

Now, remember, I will never know as much as some of you hAve already forgotten about electricity.....

 

But 4 wires? 4 Wires? Whassat about then?

 

In a sense it doesn't matter because all I need to do is crimp a new wire  (sleeved) to each end and then poke them into the switch box, connect up and switch on .

Innit?

 

 

 

 

[Jeremy Harris]

It's a two way switched lighting circuit by the look of it.  Just fit a new bit of 3+E and run it to the switch, wiring it as it was before.  You'll need 3+E for the new build, even if you don't have two way switched lights, as linked heat/smoke alarms usually need it.

[Onoff]

TURN THE POWER OFF FIRST!

 

So a two way light switch wired in "old colours", 3-core and earth. This nicked at random off the web:

 

 

Hopefully the wires are still connected to the switch? If not copy where the wires connect at the "sister" switch. The reason I say this is not everybody follows the colours above.

 

Best bet is if you can haul that bit up and replace. If not some deft crimping.

[ToughButterCup]

3 minutes ago, Onoff said:

TURN THE POWER OFF FIRST!

[...]

Best bet is if you can haul that bit up and replace. If not some deft crimping.

 

Did this before snipping 

 

so all I need to do is copy it.

 

3 and E : off to get a bit from a Shed.

 

I'll try hauling on the end of the bit of wire that I have exposed , if not cut back a good deal more.

Thanks for the support, both of you

Ian

 

 

[Jeremy Harris]

Looks like the light switch back box at the bottom of the last photo, so hopefully Ian will have left the wires connected to the switch, so they can be copied when re-wiring it.

Edited February 11, 2018 by JSHarris
Cross posted!

[TerryE]

On 21/10/2017 at 13:35, Onoff said:

This was to demo joining two bits of T&E,  2.5mm new & old in this case

Clive, just noticed this;  you are a star, BTW. 

 

Ian, You shouldn't have cut the 3+E back to the same height above the rawlplug hole.  Look through Clive's example again.

 

You'll need to hack back further now. The joins need to be staggered so that no joins are at the same level.  

 

I guess this is a bit like asking Jan about her soldering skills, but you can use twisting the copper plus soldering as an alternative to crimping.  You just need to strip back enough to slide the heat shrink beyond the hot bit otherwise it will shrink in the wrong place.  And also wrap some wet cloth or kitchen towel around the heat shrink to keep it cool.  However you achieve it, the end rest needs to be doubly insulated: once around each phase and once around the lot.