Drilled into earth

jamie_128

First time ive ever done this in my 10 years of DIY. 

Drilled into an earth cable in the kitchen, dont even know why its there it appears to be free hanging i cant hear or see any joists that it should be clipped to.

Never the less, from what i can see ive took the earth sheathing off in 3 different places, about a 3mm section at one point and then 1cm wide section at the other point so the copper wire is clearly exposed, its behind plasterboard so i cant physically touch it, the copper wire seems to be perfectly intact just the yellow sheating has been drilled off.

Do i need to cut plasterboard away to repair it with electrical tape or will it likely be okay safety wise? Nothing tripped or anything. 

The picture shows the bigger 1cm bit. 

nofoollikeold

1. If the sleeving is green and yellow, it SHOULD be an earth cable.
2. If the sleeving is yellow without green, it could be a cable for a two way light switch, or something to do with boiler cabling.  It could become live in certain circumstances.
3. In either case, but especially the second, the sheathing should be made good.  I'm not sure insulation tape is acceptable, it would be better to replace the cable from previous connection point to next.

grumbler

If it's 1-core braided cable , then it's very unlikely to be anything but earth.

Personally, I'd leave it like it is, with the damaged insulation, if the core is fine.

Unfortunately, the photo is so poor, that pretty much useless.

GDB2222

I really think you need to open up the plasterboard to investigate. It's not a big job, providing that you can match the current paint finish.   If you have say a 60mm hole saw, that will cut through easily and give you a plasterboard plug you can easily replace. I'll explain how later. 

If it's really just the sleeve on an earth wire, you can probably leave it uninsulated. Anything else, or if in any doubt, splice in a new piece of cable. Do not use choc blocks. Crimping is good, but practise first on some spare cable.

Ideally, as said above, replace the cable from one connection point to the next, but this may be quite difficult in practice.

Mickey666

I'm not sure about the electrical regulations, but in terms of actual danger a bare earth wire is on a par with an earthed copper pipe or radiator, ie no danger at all.
The key issue, therefore, is to ascertain whether the damaged wire is indeed an earth wire or, as pointed out above, some other type of cable.  The other consideration is whether the copper core has been damaged.  It's not clear from the poor quality photo, but it looks like a multi-cored earth wire.  If one of these cores has been broken then the current rating of the cable will be reduced, which could in some cases mean that the function of the wire is compromised.  Without knowing what the wire is connected to, it's not really possible to be certain.
As it is in a kitchen, could the wire be for earth-bonding pipework and/or other metal items in the kitchen (sink, radiators etc?).  Is it possible to locate both ends of the wire and if so would it be possible to disconnect the damaged wire and use it too pull in a new length of equivalent undamaged wire to replace it?

GDB2222

Mickey666 said:

I'm not sure about the electrical regulations, but in terms of actual danger a bare earth wire is on a par with an earthed copper pipe or radiator, ie no danger at all.
The key issue, therefore, is to ascertain whether the damaged wire is indeed an earth wire or, as pointed out above, some other type of cable.  The other consideration is whether the copper core has been damaged.  It's not clear from the poor quality photo, but it looks like a multi-cored earth wire.  If one of these cores has been broken then the current rating of the cable will be reduced, which could in some cases mean that the function of the wire is compromised.  Without knowing what the wire is connected to, it's not really possible to be certain.
As it is in a kitchen, could the wire be for earth-bonding pipework and/or other metal items in the kitchen (sink, radiators etc?).  Is it possible to locate both ends of the wire and if so would it be possible to disconnect the damaged wire and use it too pull in a new length of equivalent undamaged wire to replace it?

Pulling through sounds great in principle. Have you ever tried actually doing it in practice? 

It only takes a couple of cable clips to stymie that idea. Or a small hole, just the right size for the cable. Once you start pulling, you are kind of committed. 

Honestly, just cut a hole in the PB and splice in some new cable. 

donemedosh

I agree with GBD2222 best to have a good look. You never know when dealing with cable if it live or not I have seen earth cable used as a live link to a light switch. If you do cut the cable test in is not live if in doubt turn the power off. As a retired mechanical / electrical engineer trust me you don't want 240 volts going up your arm. you cannot smell or hear Electricity & if you feel it it might be the last thing you feel. If in doubt get a sparky. Hope this helps

jamie_128

thats a slightly better pic, it seems to come from upstairs i think as the sockets in the kitchen are BELOW where i have drilled into this cable and the light isent really anywhere near it either so cant imagine its from that. 

Im saying earth cable because its copper internals and the sheathing is yellow from what i can see. My live and neutral are black and blue in the house. 

jamie_128

Its all yellow so not earth, dont know where its from or going.

jamie_128

thats the position of the cable to the nearest socket, theres also a socket under the worktop. 

Mickey666

Still not very clear photos but it's looking more like a regular cable to me rather than a separate earth wire.
Also, not sure what you mean by "My live and neutral are black and blue in the house. "  Live/neutral should be brown/blue or possibly red/black for old wiring colours.  A yellow wire inside a cable is unlikely to be the earth conductor as that would normally be a bare wire, therefore yellow is probably a conductor, possibly for a lighting circuit with two-way switching.

The real problem, as mentioned above, is that it's not always safe to rely on the original work being standard and to the appropriate regs because mistakes and short cuts can sometimes be taken.  So, the usual approach is to assume the correct colours have been used BUT ALSO verify to be absolutely sure.

Having seen those new photos (even though they're not entirely clear) and now thinking that the broken wire is likely to be a conductor, I'm now tending to agree with GDB2222 that the wall needs to be opened up and the damaged section of cable should be replaced.