Drilled into Metal Conduit!!

[DITribe]

This is my first post although I have been reading much in this forum since buying my first home, so firstly hello all.

I have recently just decorated the living room (just a temporary botch) and have gone to change the wall lights. When putting on the new bracket I needed to drill a new hole just below the existing one. When I drilled into the wall I briefly met some resistance and then went into a hollow. I immediately pulled out the drill and inspected, as I couldn't really see I chiselled a little out of the wall to notice that I hit a metal conduit, as had the previous light fixing!
As I had done this I also noticed that the cable to the light had come straight from the light switch on a diagonal run of about 3ft!!!

What I would really like to know is how I check to see if the metal conduit has any live cables inside. I don't want to ruin the just decorated wall if I can help it, so should I check the ceiling void to see where it runs and what to?

Cheers
DITribe

 

[Chri5]

If the house is old, the 'conduit' black and about 12-14mm it's an old gas lamp tube.

Ignore.

If you follow the line of the conduit downward is there any sockets that might feed via this tube?

Could you detail the age of your home, state if it;s a house or flat and confirm via opening up some sockets / switches if your place is wired via conduit.

Metal conduit isn't that east to puncture, so I'm still not sure that it is what you say.

 

[DITribe]

Thanks for the quick reply Chris,

The House was built in the early 60's, and i would say the conduit was pretty easy to get through and is around the same sort of size and description that you gave (maybe a touch bigger then 12-14mm though).

There are no sockets down from the conduit just the wall light smack bang next to it.

I can check a few sockets and switches tonight and see if the cable is run via conduit.

 

[mikefear]

couldn't you just nip to the handyman and buy a stud dectector that detects voltage? probably not a proffessional thing to do like, but would do the job you ask. (the spirit of diynot)

 

[DITribe]

couldn't you just nip to the handyman and buy a stud dectector that detects voltage? probably not a proffessional thing to do like, but would do the job you ask. (the spirit of diynot)

I did go out and purchase one last night (stanley intelisnsor pro) but i'm not sure how much i trust it to be honest as it beeps at anything!!
Thats why i came on here to seek further advice.

 

[luminaire]

Have you tried using a metal/cable detector? Although not 100% accurate they can still be useful.

Also, that diagonal run should be enclosed in metal.

 

[DITribe]

Have you tried using a metal/cable detector? Although not 100% accurate they can still be useful.

Also, that diagonal run should be enclosed in metal.

I'm pretty sure that the diagonal run shouldnt be there at all. The whole room will be replastered next year so i'm leaving all the cables as they are if i can for the time being as i have the whole of upstairs to be getting on with.

Yes i have tried the metal/cable detector as mentioned above but its not really helping as it detects things when they are not there and vise versa, so can't really trust it to tell me if there is any live wires in the conduit!

 

[Chri5]

Conduit tends not to be used other than for direct runs A to B either vertically or horizontally. It also tends to be used at a full wire project rather than for smaller additions.

It may well have be part of the original fabric of the property and if it has since had a rewire that job could have ignored any existing conduit / conduit system and simply ( ) chased everything in or placed cable in floor, ceiling and wall voids.

If nothing has stopped working I'd leave it until next year when you rip the room apart.

You could try lifting the floors below and on the floor above and see if you can see any cables that use the conduit.

 

[DITribe]

Ok last night i managed to get a better look with some more natural light about. Seems to be that i have hit the cables which run from the thermostat in the kitchen, i will have to investigate this a little further to make sure. To confirm where would the thermostat run to, the hot water cylinder or the boiler?
The wire inside had been damaged. More worryingly it had been drilled into by the previous light fixing, not sure how long the previous occupiers had their wall lights up but definitely did not look safe!

If it is as I suspect and the damaged cables are running from the thermostat will it be a simple(ish) job of running through some new cable?

 

[JohnD]

screws into wires can be very dangerous. The screw may become live, and the fitting it attaches to. Fatalities have beeen known. If the conduit is not well earthed the conduit may become live and carry the voltage to other areas

Once a screw has gone in, the problem may get worse (or misleadingly seem to get better) as contacts spark and erode, or insulation melts.

You really neeed to investigate this, even if it means chipping away some plaster or running new cable in e.g. minitrunking which if run down corners (and it can be painted) is not too unsightly. I can understand you are reluctant to dig out the walls and spoil the decorations but that might seem like a poor excuse if something bad happens

 

[DITribe]

Totaly agree with the danger involved John.

I am going to change the wire as its the only option available (i'm not into risking my own or anyone elses safety for a quick fix).
It shouldn't be too hard as there is obviously already conduit in the wall that i can run the new cable through. Problem comes when i get past the wall, as i havn't manage to trace the cable that far yet. For that i need to pull up the tounge and groove chipboard floor upstairs. I have been searching the internet for some diagrams to show where the cable will go to from the thermostat. It seems to be running towards the hot water cylinder, but i want to confirm what the routing should be!

 

[electronicsuk]

Totaly agree with the danger involved John.
I have been searching the internet for some diagrams to show where the cable will go to from the thermostat. It seems to be running towards the hot water cylinder, but i want to confirm what the routing should be!

It will be heading towards the wiring centre for your central heating system, which is most likely in your airing cupboard where your immersion heater, tank stat and valves are probably located.

 

[Steve]

I had one of those stud/wiring/voltage detectors once. I held it up in the air in the dining room once, and it buzzed, indicating voltage, but it was in mid-air. Turned out it was picking up voltage 3 feet away above the ceiling, where all the cables go from the consumer unit.