Incoming power cable fault

[Richard Ford]

My son has a fault on the underground cable coming into his house and has no power at all.

The engineer sent out to trace the fault says that there is power at the sub-station and his neighbours have power.

It looks as though they will have to dig up the road and driveway to repair the fault.

Is there a way of measuring from the house fuse to determine how far along the cable the fault is, so that they do not have to dig up all

100m of driveway. Not by my son obviously.

Your comments would be very useful before the diggers move in.

Thanks Richard

[Huge]

Yes. Time Domain Reflectometry, or TDR for short (there's appropriate).

've used it myself to find faults in thick Ethernet cable.

[Tim+]

How about his next but two neighbour? The three phase mains is usually divided up as it goes along resulting in every third house being on the same phase (I believe). If they've got no power then the problem is "upstream" of your son's house.

Sorry, no idea. Good luck!

Tim

[Broadback]

If they are certain it is the cable surely it will be easier just to lay a new line. They can surely do that using mole, no need to dig a trench at all. That was what they did to lay me a new gas main.

[The Natural Philosopher]

yes.

A reflectometer will tell them where the fault is to a meter or so.

[Andrew Mawson]

If the cable has failed it is unlikely to be spontaneous but caused by some external influence like subsidence due to traffic or whatever. Personally even if located by TDR I'd be unhappy just having it jointed at the fault as it will fail elsewhere. However the most likely point of failure is where your branch cable leaves the main cable in the road.

AWEM

[Richard Ford]

They have supplied a generator to tide him over, so I guess it will take some time to repair.

[harry]

Yes. There is a gadget sends a pulse down the cable, it is reflected back when it gets to the end of the cable. It determines how far away the break is by this means, It will likely be in a joint box somewhere.

They will have a "cat and genny" To follow the route of the cable on the surface.

[The Natural Philosopher]

took two weeks to dig up and fix the 11KV here when the tractor and trucks rammed a stone through the underground

If its justs a single 250V link its probably a bit quicker.