clip on ammeters

[craig141]

Hi guys

I'm currently working on a job which requires the removal of dead cables. The problem I have is that there are some cables that are live and mixed in with the dead cables. The cables are buried for part of their run and cannot be traced, so we cannot determine the live from the dead without it being time consuming and digging out the cable. Could we use an ammeter to determine live from dead? Also does it depend on the cable, as we are removing mainly cable above 50mm and armored.

 

[Marvo]

Could we use an ammeter to determine live from dead?

You can't prove dead using an ammeter but I'm suspecting you mean can you use it to determine used cables and unused cables.

You could use the ammeter to determine which cables are supplying a load but you certainly can't prove a cable is not in use using an ammeter because some loads only run very infrequently.

 

[HandySparks]

If it's multi-core cable, not singles, a clamp ammeter probably won't tell you anything. And if it's armoured, a non-contact voltage detector is unlikely to work either.

If you can disconnect the unused cables, you may be able to trace them with suitable kit comprising a signal generator and separate detector, with the signal applied to the armour.

Someone with more experience of this will know the best bit of kit to use.

 

[gnuuser]

marvo is correct a clamp ammeter will show a current being drawn but will not show any if the load is shut off
and the line will still be live.
by no means should you attempt removal or cutting a conductor without verifying it is in fact de-energized and isolated from power
identify, verify by test, isolate and lock out, then remove the conductor
and one other thing document what is done!

 

[GMES]

You could always enlist the services of a scally for the day, they seem to be able to find and cut through the live cables...simples

 

[shanky887614]

You could always enlist the services of a scally for the day, they seem to be able to find and cut through the live cables...simples

I read a story about. A tractor tyre innertube wrapped around an axe seems to be the popular weapon off choice.

Me? I like my skin unchared so I would never try it XD

 

[electron1]

If it's multi-core cable, not singles, a clamp ammeter probably won't tell you anything. And if it's armoured, a non-contact voltage detector is unlikely to work either.

If you can disconnect the unused cables, you may be able to trace them with suitable kit comprising a signal generator and separate detector, with the signal applied to the armour.

Someone with more experience of this will know the best bit of kit to use.

We used to test cables by this method when I was an Apprentice on Area Board as it then was (Electricity Utility)
Unfortunately I cannot remember the equipment details, as it was in the late 60's.

 

[PEG]

If you are removing cables,they need to be identified,tested and disconnected BOTH ends,removing in pieces starting from preferably source end. You need to be dead sure of your job if your not doing ALL parts of this task. The ammeter idea is a bad one...

 

[nickblake]

Good answer peg

 

[shanky887614]

If you are removing cables,they need to be identified,tested and disconnected BOTH ends,removing in pieces starting from preferably source end. You need to be dead sure of your job if your not doing ALL parts of this task. The ammeter idea is a bad one...

Could quite simply find cable using long lead method.

 

[Engineer54]

Hi guys

I'm currently working on a job which requires the removal of dead cables. The problem I have is that there are some cables that are live and mixed in with the dead cables. The cables are buried for part of their run and cannot be traced, so we cannot determine the live from the dead without it being time consuming and digging out the cable. Could we use an ammeter to determine live from dead? Also does it depend on the cable, as we are removing mainly cable above 50mm and armored.

Then time consuming it will have to be then!!

 

[thebigcheese]

Is leaving them in not an option?