insulation over wires or not?

[martlewis]

I have had my shed wired by a spark but now I want to insulate it.

Construction is wood panels covered entirely on the outside with roofing felt (a temporary waterproofing measure for the winter as I had a lad of the stuff hanging around. In the summer I'll be cladding over this with shiplap wood so it looks a bit nicer in the garden.

On the inside I will be putting 100mm loft insulation on all walls and roof, and then covering with something like ply or chipboard.

Should I insulate over the wires leaving them between the outer wall and insulation, or should I insulate behind the wires so they are between the insulation and the inner wall? I don't want the wiring exposed inside.

 

[ricicle]

Did you advise the electrician of your intentions when he wired it, as he should have worked out his cables to suit the fact that they would be in contact with thermal insulation?

 

[martlewis]

Insulating wasn't going to be a factor but things change, hence I'm asking the question here.

 

[martlewis]

Does anybody please have any advice on this subject?

 

[Softus]

As ricicle has already said, insulating the cable will affect its current rating, so you need to consult the electrician who installed it.

 

[joe-90]

+++ unhelpful part deleted +++ If you can run cables around central heating pipes then a few feet of insulation in a draughty shed isn't going to affect things is it? It is?? +++ unhelpful part deleted +++

 

[joe-90]

It means that if the cable size has built-in tollerance to cope with hot central heating pipes - then a couple of feet of insulation in a draughty shed is here-nor-there.

+++ unhelpful part deleted +++

 

[joe-90]

+++ unhelpful part deleted +++

 

[joe-90]

+++ unhelpful part deleted +++

If the correction factors mean that you cannot run a 2.5mm power cable across a drafty shed behind insulation - then they certainly cannot run 2.5mm power cables across a house in the same space as central heating pipes. The shed is a benign environment, whereas as the heating pipes are extreme. +++ unhelpful part deleted +++

 

[joe-90]

+++ unhelpful part deleted +++

 

[Big_Spark]

Well in fact, despite the manner of the posts, Softus is actually right, as is Ricicle.

Installing Insulating materials on top of cables will have a direct and attributable effect on the current carrying capacity of the cables as they are unable to efficiently dissipate heat generated within them. However I would add that as this is a shed in the garden, and the loadings on the circuits may be minimal, it is unlikely to be a significant difference, BUT I do agree with Softus and Ricicle that perhaps a conversation with your Spark and a full review of what you are now going to use the shed for is required to be safe. It is better to be safe than sorry.

 

[joe-90]

Well in fact, despite the manner of the posts, Softus is actually right, as is Ricicle.

Installing Insulating materials on top of cables will have a direct and attributable effect on the current carrying capacity of the cables as they are unable to efficiently dissipate heat generated within them.

Which is an effect that is not encountered when in contact with hot water pipes? Go into your loft and leave a few lights on. Feel the cables( which will be under the insulation) and they will feel cold.

Now take up the boards on your landing and feel the cables with your heating on. They will feel hot to the touch.

Which one is dissipating heat? Which one is an extreme environment?

 

[holmslaw]

..

 

[Big_Spark]

Joe, we are not talking about that and you know it. No-one has said your comments are wrong either, we have all simply said that the effects of the insulation should be accounted for. They are, in all liklihood negligable and not anything to be concerned about, but as we do not know the way he intends to use the circuits in his shed and what loads they will be under we cannot simply say ignore it.

Geddit?

 

[joe-90]

+++ unhelpful part deleted +++