Loft insulation

Long delayed DIY project coming up - planning to insulate loft at ceiling level. But I've seen a couple of websites saying not to put insulation over electricity cables, and I have several cables up there. Is this really an issue?

Many thanks

Reply to
JIP
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Only if you are running em flat out

Reply to
The Natural Philosopher

And they are shower or cooker feeds. And all that means is some calculation is necessary.

Lighting and 32A rings are generally OK unless a lot of things are conspiring to work against you.

The other main issue is downlighters which will need hoods over them otherwise they will overheat.

Reply to
Tim Watts

The caculation is easy on these. Move the cables out of the insulation. They will almost certainly be run at near to full load.

Adding insulation over a 2.5 T&E cable used on 32A ring would be wrong if it the insulation makes it installation method 101 or 103

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The hoods are only needed for fire protection between floors when required by part B of the building regs.

Reply to
ARW

Well I have no idea what most of the cabling is - it was all done before I bought the house. But the cooker and shower are at a far end, so I doubt if they are involved. Most of it seems to be lighting, but no downlighters involved.

Many thanks

Reply to
JIP

Correct me if I am wrong, but I thought it was considered necessary to provide some space around a downlighter buried under insulation.

Reply to
Tim Watts

On 07 Sep 2014, "JIP" grunted:

Those cable will be fatter than the others, as they are intended for higher current. In the same way that ring main cable are fatter than lighting cable.

Reply to
Lobster

No.

If my house burns down, I'll let you know.

Reply to
Huge

Yes - sorry - you are right. I was stuck on thinking 100mm insulation or less for some reason which is OK. But not for >100mm

Reply to
Tim Watts

I cut 4" soil pipe to the length of the first layer of insulation (170mm ?) and cut holes so they poked through and were flush with the surface of the insulation then just ran the top 100mm layer over the whole lot.

Much cheaper than the commercial alternatives.

:)

Reply to
0845.86.86.888

I'd not have said so myself. Most of the loft insulation here is over cables. If a cable is getting even warm I'd imagine that would mean a problem to start with.

Brian

Reply to
Brian Gaff

Interestingly, I noted a person was using pieces of pipe around downlighters to act as heat loss areas in the insulation. However downlighters and power transformers and psus are a whole other situation. I've often wondered about the safety of such things if they get hot in use. Brian

Reply to
Brian Gaff

Thanks for all the replies

Reply to
JIP

But does a fire hood supply the required space?

Reply to
ARW

Honestly - not sure...

Reply to
Tim Watts

The 35W downlighters (12V) in our hall began giving trouble a wee while bac k. Investigation showed that my rather vague attempts at allowing a heat p assage through the insulation some 20 years previously had not been that su ccessful as not only had the holder contacts deteriorated but the choc bloc k connectors looked somewhat melted too.

There's now 2 x 3W of LED in each position and the holders are barely warm

- and the lighting is far better too ! Rob

Reply to
robgraham

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