240 v electrical wiring in wall cavity - Stuartli
>>to route electrical wiring through wall cavities>>

I presume that my property (built in the 1880s and rewired about 12 years ago) will have the electrical cables running in the wall cavities as well as under the floorboards.

About six weeks ago we had cavity wall insulation installed (free courtesy of PowerGen, along with additional loft insulation) and the fitters, who knew their stuff on the legal requirements, never mentioned anything about electrical wiring.

I should imagine that the flue for the hall gas heater would reach higher temperatures and this was one aspect that the fitters made a point of checking.
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What\'s for you won\'t pass you by
240 v electrical wiring in wall cavity - pmh
Remember the cables will probably be part of a ring circuit (not a spur) hence the current taken is not necessarily what is as a result of what is connected at the socket. It will be approx half of the total load on the ring, which can easily exceed the 30A fuse rating. The fuse will not blow for quite some time even at higher currents.

Cables are also derated when in a confined space. So if you are in any doubt get an inspection done by an approved contractor, (I think it is a a PIR but you will need to to discuss this). Remember regulations are changing frequently, and an inspection will probably throw up the ' not to current standard' type of statement. This will not necessarily mean that it is any less safe that last week but may advise work that is deemed sensible. It should at least keep your insurer happy.

Look at www.niceic.org.uk/consumers/pir.html
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pmh (was peter)


240 v electrical wiring in wall cavity - adverse camber
"About six weeks ago we had cavity wall insulation installed (free courtesy of PowerGen, along with additional loft insulation) and the fitters, who knew their stuff on the legal requirements, never mentioned anything about electrical wiring."

Well they should have done, so they obviously didnt know their stuff as well as you thought. It has nothing to do with the temperature that the wires get to being a fire risk - which is why they worry about flues. Some cavity wall insulation products are known to degrade the electrical insulation of cables. The rating of electrical cables is lowered if they are insulated.

240 v electrical wiring in wall cavity - adverse camber
It has nothing to do with the temperature that the wires get to being a fire risk

I meant of course a fire risk to the wall insulation.
240 v electrical wiring in wall cavity - Stuartli
>>Some cavity wall insulation products are known to degrade the electrical insulation of cables.>>

No mention of any potential problems in this area on the technical sheet, which I had to sign after the work.

The firm involved does PowerGen's insulation work all over the North West so I'm sure that if anything untoward could occur then it would be well aware.

What type of cavity wall insulation products are you aware of that might cause problems?
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What\'s for you won\'t pass you by
240 v electrical wiring in wall cavity - Gromit {P}
"What type of cavity wall insulation products are you aware of that might cause problems?"

Polystyrene based insulation, for one. When heated, these can degrade to give off styrene which acts as a solvent for the polymer-based insulation on the cables.

As suggested, get a second opinion from a competent electrician. Better safe than sorry!
 

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