Remains of Lamp Post

[Rod]

Digging a hole for a fence post, I suddenly found an underground void. Maybe I should have been expecting something because it is near a utility lamppost (on our property, but there is some sort of right in the deeds to allow the post, so I have no argument about that). Said lamp post was replaced a year or so ago a couple of feet away from the old one, but I thought the hole had been filled in.

What I actually saw was the base of the post (a metal tube, broken off, starting a few inches below ground) surrounded by concrete. Down the middle is a cable with a metal strip winding. Hopefully that is all just about visible in this picture:

Luckily I can revise the fence plans and avoid this spot. But I am not happy that the lighting people can apparently leave their rubbish in our garden. Do they not have to remove it along with the post? And I have no idea if the cable is live or not. (I'd assume not, but have no intention of taking any chances.) Seems I could put some soil back and ignore it. Or I could complain and try to get it removed or at least checked for safety.

What would you do?

(BTW The Lidl SDS has four positions. Rotate/Rotate and hammer/Hammer and free rotate/Hammer locked. The hammer and free rotate position works quite well with the 'spike' as it helps to avoid it binding into a lump of something hard.)

[Keith W]

Sounds like you should be asking this on one of the 'legal' sites.

[Rod]

In some ways, I agree. But I feel confident that someone here will have had to deal with this sort of issue in a practical way. I don't really want the legalistic answer for now (though I would be interested to know what that is).

[Roger]

Not even be remotely bothered and find something else to do.

[gazz]

i'd test if the cable was still live, and if it was i'd wire the house up to it :)

[ARWadsworth]

I would test the cable to see if it is live.

Adam

[The Natural Philosopher]

If it is, short it out and blow a fuse upstream. Problem solved.

[Andrew Gabriel]

It's very unlikely to be, but that advice is extremely stupid, as if it is, it could well come directly from the street mains with a very short cable and high PSSC, and given the cutout has gone, you're probably looking at blowing a 400A or higher fuse, resulting in risk of severe flash burns to yourself. If it's a long cable from the street mains supply, it might take a while to blow the fuse or the cable. (Street lighting supply cables often well undersized for the fault current protection upstream of the cutout, and the cable will often burn out on a cable fault since it would have to be replaced anyway. This is suppliers works, and BS7671 doesn't apply.)

[Jules]

Using a stick, prop the business end of a spade up above the remains, retreat to a safe distance, then throw a rock at the stick.

[Tim S]

The Natural Philosopher coughed up some electrons that declared:

That's a possible fuse rating. You're more likely to get *many* kA, perhaps as much as 10kA on a dead short on a short cable jointed to the main cable, depending on of course distance to substation etc.

If I put a dead short on my meter incomer, I would get 1.2kA fault current and that's on a 7-8m bit of weedy cable from the street.

[The Natural Philosopher]

Would you indeed. We put a digger through mine. No effect at all. Just blew the 100A fuse.

[Tim S]

The Natural Philosopher coughed up some electrons that declared:

Based on measurements with a calibrated Megger, well, yes.

A BS1361 fuse will take around 1/2 hour to blow at double its rated current.

0.1sec will take 1kA thereabouts.

The danger scenario is when the device causing the fault either creates an arc or vapourises - neither of which you want in your face. The OP's scenario is rather different to sticking a solid lump of metal through a cable swiftly whilst both are covered by soil (presumably).

Cheers

Tim

[PeterC]

Very disappointing incident at work: JCB through 11kV incoming supply. There was a flash and bang but confined to the pit; JCB a bit scarred on the scoop.