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Damp pyro


All the electrics in my flat are in Pyro cable, and yesterday I was having my ceiling plastered and the plasterer caught the lighting cable with his trowel. Although this did not blow the fuse instantly, it blew a few seconds later - after I assume moisture got into the cable.

Does this cable dry out?

If not, how can this be fixed please? The cable is on the edge of a ceiling, and disappears through the wall, so cannot be easily stripped back.

Thank you in advance.

2 Answers from MyBuilder Electricians

Best Answer

Unfortunately this is not an easy fix, if the pryo or MICC as its really called has been punctured at a point somewhere along its length by the plasterers trowel then really that section of cable needs to be replaced as MICC is difficult to workl with and is seldom used these days. if the MICC is buried in the ceiling its unlikely it can be cut back,to fit two new pots and glands etc.

The problem could also be worse if its imperial MICC as getting the pots and glands to fit it would be nigh on impossible. Metric MICC pots and gland etc are still about but not readily available.

The best course of action really is to get an experienced electrician round to take a closer look, and advise on what action can be taken. Doing nothing and hoping it will dry out is not an option.


Answered 9th Nov 2011

Mineral Insulated Copper Covered Cable (MICC) sometimes called Pyro one of the best cables invented lasts forever except if Damaged the insulation is a powder called Magnesium Oxide I believe, but it is highly absorbent and takes in moisture very easily which is why it has a special termination a brass pot filled with Compound to stop water ingress. unfortunately you cannot repair it without cutting back at least 300mm to 450mm then you could probably re use the existing Gland,Pot, etc with new compound, you would need an experienced spark who still has all the right tools to strip the outer sheathing a Ringing tool, a Pot Wrench and a Crimper I have all the tools and the know how but it may not be your cheapest option, I have heard of someone chasing the damp back out of the cable with heat but it is unlikely to work and you could not reseal a damaged section you may have to totally replace the section of cable, with a new PVC/PVC cable.The plasterer should have third Party liability insurance and you should ask him to foot the costs completely it is his fault not yours. as an electrical contractor we have £5,000,000 of insurance cover so if we
damaged your plaster we would be insured and you would be covered. all the MICC parts are still obtainable and all the sizes are marked on the side of the pot and Gland so its easy.
I hope this helps if it does hit the like button


Answered 10th Nov 2011

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