I have some armoured cable in the garden left by the previous owner, the cable looks like its been installed by an electrician with an RDC and the armoured cable running all the way to the consumer unit. The problem i have is when i peeled back the cable to install an external socket etc...all of the five cores are unmarked. I have a live wire detector but can you advise on the best way to identify the the other four wires. ? Thx
Five core armoured cable identification
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Surely the place to start is to look in the CU?
See how the cores are arranged in there?
See how the cores are arranged in there?
You can't just start using that without testing it. Apart from identifying the cores, you need to test earth fault loop impedance, polarity, insulation resistance. You need to find out the length to check that voltage drop will be OK, and then measure the conductor resistances to verify.
So you know the cable is, at least in part, connected to a circuit suitable for sockets?
What do you mean by "etc"?
How are you going to gland the cable into a socket? How will you then continue on to the etceteras?
No identification marks, e.g. numbers, at all?
By looking at the other end, and if you can disconnect everything at both ends by a series of continuity tests using the multimeter which you should have instead of a "live wire detector".
This is the sort of thing you get in Logic Problems books, isn't it?
At one end, label them ABCDE, at the other 12345. Join A to B and C to D, and check continuities. Now join B to C and D to E, and check again. I assert that this gives sufficient information to determine which core connects to which. Do you believe me?
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Personally I would short each to earth, one at a time.
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So... they're all the same colour?
How can a "live wire detector" help when there are no live wires in the cable
Or is there a live wire because it is connected at the consumer unit ?
Or is there a live wire because it is connected at the consumer unit ?
Sounds about right, but I'd have to do some scribbling to be sure!
If you wanted to save yourself one journey from one end of the cable to the other, you could just connect moderate value resistors, of appropriately chosen (different, and not multiples of one another) values between A-B, B-C and C-D and then measure resistances at t'other end.
Kind Regards, John
Lots of running from one end to t'other, unless you have a helper!
Kind Regards, John
When I shadowed a chap at the DNO for work experience, we beeped out a 3 core HV cable from one side of the town to the other. It was marked 1 2 3 at both ends, but this was to be checked, as jointers would often not joint to numbers, but to where the cores wanted to sit.
We used a resistor. One core shorted to earth, one through a 2K resistor, and one open ended.
These days it would be done with phones and a couple people.
We used a resistor. One core shorted to earth, one through a 2K resistor, and one open ended.
These days it would be done with phones and a couple people.
It is just a garden....
I know, but the more esoteric methods of identifying the conductors are more fun
I also suspect that some people would (will?
) say that nothing short of end-to-end continuity of each conductor prior to energising would be acceptable!Kind Regards, John
Yep, that's essentially analogous to what I suggested for the 5-core.
Kind Regards, John
If the 5 wires are arranged in a ring then short one wire to ground. Label it as number 1, label the other wires 2...5 working clockwise....
At the other end find the wire that is connected to ground. Label it number one and then working anti-clock wise the wires are 2...5
If no ground possible then short two wires together and they are 1 and 2
99 times out of 100 this works as the lay of the wires in the cable is constant along the length.
That said check the installation before powering up.
At the other end find the wire that is connected to ground. Label it number one and then working anti-clock wise the wires are 2...5
If no ground possible then short two wires together and they are 1 and 2
99 times out of 100 this works as the lay of the wires in the cable is constant along the length.
That said check the installation before powering up.
I've never seen a multi core armoured where the cores are not numbered :s
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