Trying to find a buried cable

Roen

Hi all,

Just wondering is there a handy way to find a buried cable.

One end of it is in my attic, unattached to anything, it's just lying loose. The other end is buried somewhere in about 10x5m of an area where there was planning permission for a block garage granted.

The cable in the attic is SWA. So far by digging a test trench I've found nothing.
Outside of that area I have found the end of what looks like NYMJ, or just T+E run in a conduit (not sure tbh).
So I guess it's unlikely that an electrician would join a cable underground like that so I'm half ruling that cable out.

So would there be a way to send a signal down the attic end of the wire and have a cable detector pick it up under ground outside or am I sticking with the crow bar for digging up the rocky soil?

Atlantic Dawn

Would one of those stud/cable detectors not be able to find it? (depending on how deep it is)

Roen

Atlantic Dawn wrote: »

Would one of those stud/cable detectors not be able to find it? (depending on how deep it is)

Do those gadgets only work if the cable is live? I just assumed so.

Roen

Rang a hire place and they were saying the cable would have to be live alright.

clintondaly

Maybe a metal detector although you may find more than you bargained for

foxy farmer

Roen wrote: »

Rang a hire place and they were saying the cable would have to be live alright.

Not necessarily. You can get a signal generator that you connect to to the cable which sends an intermittent pulse through the cable. You then use a cable detector to pick up the pulse. Cable cores would have to be shorted at far end though i think.

meercat

Have you tested the cable you’ve already found. The one in the conduit (continuity testers should do)
The other end of this cable might be inside your consumer unit as the attic isn’t much good to you (unless it’s a bungalow)
The simplest and best option may be to install a new cable. Save your time and money hiring a cable detector

babi-hrse

Tone and probe
Earth one leg of tone it makes it amplify
Wave probe around approx area of where cable is you may hear the tone coming through. Fluke do a decent tone and probe. If the short light comes on during toning your at nothing with the cable unless you have a second pair on it it's no use.

babi-hrse

To identify a clean pair.
Bite both legs of a pair with tone and on other end of cable strip off insulation on end then put your probe against bare metal and touch other leg off probe too. If the high pitched warbling ceases and all that can be heard is buzzing you have a clean pair.

Roen

meercat wrote: »

Have you tested the cable you’ve already found. The one in the conduit (continuity testers should do)
The other end of this cable might be inside your consumer unit as the attic isn’t much good to you (unless it’s a bungalow)
The simplest and best option may be to install a new cable. Save your time and money hiring a cable detector

Hi,

The cable in the attic was left there to be connected to the fuse board (consumer unit?) once the sheds were built. It's just above the fuse board in the bungalow.

It runs along the attic, down the wall and under the ground into the yard.... somewhere.

To install a new cable would mean a lot of kango work and re-laying a concrete path and potentially going under/through a retaining wall. It'd be a last resort but it's always on the cards alright.

I'm familiar with continuity testers from a networking point of view but always had both ends of the cable available. I assume electrical testers are the same.

Cheers for the input, I'll find this bloody thing eventually!

meercat

Roen wrote: »

Hi,

The cable in the attic was left there to be connected to the fuse board (consumer unit?) once the sheds were built. It's just above the fuse board in the bungalow.

It runs along the attic, down the wall and under the ground into the yard.... somewhere.

To install a new cable would mean a lot of kango work and re-laying a concrete path and potentially going under/through a retaining wall. It'd be a last resort but it's always on the cards alright.

I'm familiar with continuity testers from a networking point of view but always had both ends of the cable available. I assume electrical testers are the same.

Cheers for the input, I'll find this bloody thing eventually!

Could the cable you found outside be in fact the other end of the swa cable that you’ve found in the attic?
If it’s already terminated into a box outside then the inner cables may look like a nymj/t&e cable as you seem unsure
A simple continuity test will confirm this as you’ve already said you’ve half ruled it out but have you tested it?

Roen

meercat wrote: »

Could the cable you found outside be in fact the other end of the swa cable that you’ve found in the attic?
If it’s already terminated into a box outside then the inner cables may look like a nymj/t&e cable as you seem unsure
A simple continuity test will confirm this

Get you now, I thought you had misunderstood my original post but it was me getting you wrong.
It's definitely a good place to start alright! If worse comes to worse I could always dig back from that end I found and see.

Roen

So the cable in the yard is solid 5 core.





The cable in the attic is stranded 3 core. For the hell of it I shorted the neutral and earth in the yard and ran the continuity test on the lad in the attic. Nothing I am afraid. Heartbroken.

So unconnected it would seem. What's the craic on the stuff in the yard though? Not familiar with 5 core stuff, heard of it but not sure what the other two would be..3 phase or two signal carriers?

meercat

Garden cable looks like 5x1.5 nymj.probaby put in to control garden lights
5 core could allow 3 switches to control lights/pond etc
May be other end is behind a switch somewhere (needs to be rcd protected to comply with current regs)


Doesn’t resolve your issue of finding buried cable though

Roen

Makes sense alright. There's two garden lights already in the site and a outdoor socket and TV point.

Cheers for the help all!

Roen

So the previous owner wired garden lights to an outdoor socket. The nymj wasn't connected back to the socket thankfully but two other lights were.

When I tried the lights the RCD for the house tripped. I knocked off the main house breaker and disconnected the lighting from the socket.

Upon loosening the screws from the socket trapped water started dripping out the bottom of it.
I'm done with it at this stage.

Proper sparks time needed to sanity check ****.

Still no sign of the initial cable I went looking for but at least the area is a bit safer.

Roen

At last. Hired a metal detector and found the conduit where it exited under the path and dug a series of holes along til I found the loop.

So phase one complete.
Now for an electrician to extend to shed, wire in shed, and connect back at fuse board.

Cheers for the help.
R.