What is the easiest way to pinpoint where a T&E cable has been damaged

It depends on the nature of the damage. If it really is a dead short, then a decent Ohm meter should give you a rough idea of the distance along the cable to the fault (knowing the resistance/m of the conductors you're testing between) - I did that sort of thing successfully once to find a JB where someone had tried to extend a ring using a single joint box - connected L & N correctly but connected the two original ring c.p.c.s together on one side and the two extensions together on the other.

If it's less of a dead short and more the usual bridge of charred remains of insulation that mucks up an insulation test, then that method won't work.

If a conductor is broken, then (with extreme care!) energising the faulty conductor from one end and tracing using a volt-stick can work (but might come under the "don't try this at home" category).

I've seen some impressive results in the past from a TDR (time domain reflectometer?) - which is like radar but inside a cable and gives a length of cable to the fault - but probably isn't cheap to buy or even hire.

   - Andy.

AJJewsbury said:

I've seen some impressive results in the past from a TDR (time domain reflectometer?) - which is like radar but inside a cable and gives a length of cable to the fault - but probably isn't cheap to buy or even hire.

Invaluable for copper comms cable testing.

They are nowhere near as expensive as they used to be. Whilst a lot of the very cheap ones are aimed at data/comms (twisted pair/coax), I think you can pick up a Megger TDR cable fault locator for not much over £1K.

AJJewsbury said:

I've seen some impressive results in the past from a TDR (time domain reflectometer?) - which is like radar but inside a cable and gives a length of cable to the fault - but probably isn't cheap to buy or even hire.

Invaluable for copper comms cable testing.

They are nowhere near as expensive as they used to be. Whilst a lot of the very cheap ones are aimed at data/comms (twisted pair/coax), I think you can pick up a Megger TDR cable fault locator for not much over £1K.