Can I bury pyro cable?

Rednadnerb wibbled on Wednesday 17 February 2010 20:35

Now I'm not sure. I called it pyro because that's what the man from the electricity board called it when he came round to do a survey for moving the meter (which is not going ahead because we need our neighbours permisson). It is a bright orange cable about 10mm thick. I assumed it was plastic coated because it is shiny but I don't know and I have no idea what is inside.

Genuine pyro is one of the cable types (being encased in earthed metal shielding) that does not require RCD protection. If you nail through it, you will probably blow the service fuse where the supply comes into the building.

Rednadnerb wibbled on Wednesday 17 February 2010 22:53

It matches in description. Can you see the termination on either end? Does it look anything like this:

If it is, further to John Rumm's comment, treat it as you would armoured cable - ie yes you can bury it without worrying.

In fact pyro is probably one of the best cables for transport of electricity through a house structure - smaller than armoured, inherently safe if penetrated with tool/nail and further, will not fail in a fire (unless the fire gets hot enough to melt copper!).

It was mandated for that house that the woodman built of timber and straw bales somewhere in Sussex (Grand Designs IIRC), being less at risk of failure or starting a fire as it was being buried up against combustable materials (the straw).

No - that's fine.

The nail would pierce the outer copper first before touching the line and flow the fuse, etc.

Pyro was used to stop animals nibbling it. And starting a fire.

Baz

Baz wibbled on Thursday 18 February 2010 15:24

Good point - I bet straw bales are attractive to mice.

One of the best DIY projects ever - can't get much more DIY than grow and season your own lumber! I did follow up on the web a while back - seems he's married, got a sprog and is having a pretty nice life. Not bad for a woodman :) He's damn well earnt it too.

They did a 'revisited' which showed this. Super prog. Up there with the hexagonal house in the fens - also built by the owner with little outside help.

Not sure if it was mandated, I got the impression from the film that Ben (sensibly) chose it given the circumstances. Kevin made a comment about it being expensive, and the reply was that it was cheaper than rebuilding!

The bit we saw looked like lighting wiring - and I thought he had low volt DC lighting to run off his battery system?

That one ended-up for sale, which I don't think you'd do by choice after the effort they went through.

Didn't know that and so sad. They seemed so happy there.

Possibly, unless he also had an inverter. Still even for low volts high current apps, it would probably not be a bad choice in straw bales.

Either that, or following the publicity someone made them an offer too good to refuse...

or they got the building bug and wanted to build another better one..

Or health reasons, hopefully not.

With Pyro the fusing must disconnect the fault or it becomes a long MICC heating element :-) Clearly in modern installs this is a non- issue even if just MCB, but a nail in a fuseholder to a faulty welder would not be good news.

Pyro is perfect re rodent attack & aesthetics at end wiring accessories, SWA is too bulky although 1mm steel probably harder for ratty to chew through. Modern BS8436 too tasty for rodents, I assume no-one has tried insudite insulation inside a copper tube (ok, cue to

You can also hammer it pretty flat before you get any problem, as the copper and magnesium oxide insulator compress at about the same rate and maintain separation (providing you don't burst the sheath). Indeed, that's how it's made - they start with a much thicker cable, and roll it down to the sizes required.