Difficulty replacing a damaged cable

[Taymar]

I'm another in a long line of numpties who has failed to test where the cables are in a wall before drilling through, in order to put some spice racks up in the kitchen. It's something that both of us are diligent about (but not on this day).

We discovered our mistake when the heating/hot water control panel below where we drilled, had no display. We took this off to expose the plate and saw that there are two separate cables that feed in to it. We then identified (by gently pulling the wires and placing something in the drill hole and seeing it move) which of the cables was damaged - the power cable.

So, having read advice here and elsewhere, and speaking to an ex-spark, now B&Q assistant, we opted to do the following...

As it's on an outside wall, the cables are embedded in plaster, so we're not keen to dig it out and replace the damaged section. We found where the cable comes out in the attic and thought the best option was to replace a large section of cable by attaching the new cable to it and pulling it through. We'd then connect the new and old, undamaged cables with a junction box.

We attached the new cable and tried to pull it through in the attic, from the kitchen. It moved about one inch, and that was that. We then tried it the other way and again, it wouldn't budge any more.

I don't know if it's snagging on something, somewhere, or if it's simply a case of there not being enough room within the channel in the wall. If the latter, is there any merit in pulling through both of the cables (including the undamaged heater cable) in order to free up more room in the channel. Or, would the cable have been clipped/clamped in place (if that's the right term for those little 'r' shaped pins)? The house is around 20 years old. If those clips have been used, do we have any hope of pulling the wire through?

And advice would be welcome. I'd rather not have to contemplate making a large hole in the wall and then once the cable is repaired, then having an unsightly box or plate on the wall. The reason for putting spice racks up was to free up worktop space as our kitchen is tiny and this is the only place where they could be put up.

So, any advice that you could give on either how to get the cable to move so we can pull it up/down through the wall, or how to repair in an unsightly manner, would be appreciated.

 

[simpson93]

this is the whole reson part p building regulation was invented, because a politicians daughter died from putting up a spice rack and dieing from electric shock, anyway back to your cable. have you tried lube? if its a conduit/pipe would help alot really depends how its installed in the wall if you hit the cable its probably just plastered over or in capping/ovalplastic conduit which is very hard to pull threw if your cables arnt straight or if theres more then one. in which case it would be easier to dig out the cable and repair then position the spice rack over the damage ^^

 

[ban-all-sheds]

So, having read advice here and elsewhere, and speaking to an ex-spark, now B&Q assistant,

Was this him?

I don't know if it's snagging on something, somewhere, or if it's simply a case of there not being enough room within the channel in the wall.

It's 99.9999% certain that the cable is under capping, not in conduit. Under ideal circumstances that's not designed to have cables pulled through it, and your circumstances are not ideal - you've put a drill through the capping and have made it even tighter at that spot.

If the latter, is there any merit in pulling through both of the cables (including the undamaged heater cable) in order to free up more room in the channel.

You may as well give it a try - you've got nothing to lose.

Try pulling a line through which you can then use to pull cables with.

But don't spend much time on it - it's almost certain that you'll get nowhere, and sill have to cut the entire length free - by the sounds of it you don't even have enough slack to be able to do a repair in situ, so you've got 2 choices:

No heating or hot water.

or

Cut into the plaster from the control unit up to the ceiling.

 

[ban-all-sheds]

this is the whole reson part p building regulation was invented, because a politicians daughter died from putting up a spice rack and dieing from electric shock,

No it isn't.

And in any event Taymar was putting up a spice rack, not doing electrical work, and that does not fall within the scope of the Building Regulations.

Nor is there any suggestion that the cable he drilled through was installed in a way which would contravene the Building Regulations (or the Wiring Regulations):

the heating/hot water control panel below where we drilled

It was in a recognised Zone - the only person who has done anything wrong is Taymar. Certainly not the installer of the cable.

 

[Lectrician]

I assume two 1mm twin and earths.

If it as me, I would open up where you have damaged it slightly to clear any burrs off the conduit (hopefully it is oval conduit, you will soon see). If it is capping, it may still work, if it's clipped, you have no chance.

I would pull out the damaged cable and then attach a new cable to the cable remaining in the wall. Strip the cables and attach by twisting two of the cores tightly together and applying a little tape. Don't let the joint become larger than the diameter of the cable. Then pull this new cable up through. Once it's through, attach a second alongside this new one with tape, and then keeping the flat cables nice and flat and straight, have someone gently push them while someone gently pulls.

 

[jamesmcbride]

a bit of lube may help if it is conduit:

http://www.3mselect.co.uk/p-1486-3m...1-litre.aspx?gclid=CIbKwfH_mLICFVMbtAodm1oA0Q

 

[OwainDIYer]

you might replace the central heating programmer with a wireless one, with the base unit attached to the cables in the loft or near the wiring centre.

 

[Taymar]

Thanks for the replies.

Yes, it was in the Zone; I stupidly made the assumption that the wiring would run straight up from the centre of the heating controller.

The controller wiring comes out into a metal box (behind the controller). As it is embedded in the wall, we've not taken it out so cannot see what sort of channel the wires run up the wall in. This patch of kitchen is tiled, but is plastered where we drilled.

I think (and can't check this as I'm at work, but could ask OH at home) that in the first floor, a dividing wall is directly above where this wire runs up. This wall divides the bathroom from son's bedroom. Will text OH to check measurements to see if this is the case. If so, it might make replacing the wire even more difficult.

Wireless controller might be the way to go. Will post back later re: upstairs wall.

 

[Taymar]

An update...

OH has determined that the wire isn't behind the dividing wall upstairs as I'd feared. However, it runs up 10cm from this wall in the tiled bathroom. Digging the cable out of the wall is not an option, it would seem.

 

[Taymar]

Right now, it looks as though we've only got two options left if we're unable to pull the existing cable(s) through (which we'll attempt again tonight). Either go wireless, or use the junction box in the attic as previously envisaged, but route it out of the attic via a different path.

A quick browse online suggests that wireless controllers are in excess of £120. As there's a good chance that we'll move house next year, I'm reluctant to spend a lot for something we'll get little benefit from.

So, that leaves a new route. If we go for this option, it will need to come down through the attic, into a bedroom and then into the kitchen. Is it acceptable to run it down on the surface of the wall, but enclose it in a conduit? Are there any particular considerations that we need to take into account?

 

[Mursal]

Ensure all circuits are dead

Make a bit of room around the area and do a solder repair. You may need to run a new wire down to the controller to give yourself a bit to work with. Stagger all joints and shrink wrap insulation over each. Then with a piece of identical conduit, split and cover repair. Hard wall to finish. Sand and paint

Or go for the wireless option, brilliant

 

[OwainDIYer]

So, that leaves a new route. If we go for this option, it will need to come down through the attic, into a bedroom and then into the kitchen.

Although it may be conventional, does it have to be in the kitchen? Assuming it's an old CH+HW timer, and not a programmable thermostat, it's not sensitive to room temperature and could quite sensibly go in an upstairs airing cupboard or on the landing.

 

[Iggifer]

i changed the switch drop in my bedroom recently, and initially it would only move a little, upon closer inspection from above, when the room had been plastered, the plaster had gone over the top of the capping and into the chase slightly, a bit of careful poking and prodding freed up a lot of space around the top of the chase and then the new cable pulled through really easily

 

[Taymar]

Although it may be conventional, does it have to be in the kitchen? Assuming it's an old CH+HW timer, and not a programmable thermostat, it's not sensitive to room temperature and could quite sensibly go in an upstairs airing cupboard or on the landing.

This is probably what we'll go for, but will ponder tomorrow before deciding for sure.

Went back into the attic and tried to pull both of the cables, but to no avail. The minimal movement we had experienced must have been a tiny bit of slack; certainly don't get the impression that either cable will budge at all.

 

[securespark]

You're in the loft tugging a cable that terminates in the (presumably GF) kitchen?