Loft Insulation and wiring!

Canucklehead

Good evening: Another excellent source of info re: potential impact of loft insulation on wiring... http://www2.theiet.org/Publish/WireRegs/WiringMatters/Documents/Issue15/2005_15_summer_wiring_matters_current_ratings_cables_in_thermal_insulation.pdf

HTH

Canucklehead

espresso

Canucklehead wrote: »

Good evening: Another excellent source of info re: potential impact of loft insulation on wiring... http://www2.theiet.org/Publish/WireRegs/WiringMatters/Documents/Issue15/2005_15_summer_wiring_matters_current_ratings_cables_in_thermal_insulation.pdf

HTH

Canucklehead

Which basically says that there is no problem.

From personal experience, all four properties in our family, built by different builders, have fibreglass insulation laid over the electrical cables in the loft. These properties were built to the building regulations required for the National House Building Council 10-year warranty. None of these have burn down!

:rolleyes:

Canucklehead

espresso wrote: »

Which basically says that there is no problem.

From personal experience, all four properties in our family, built by different builders, have fibreglass insulation laid over the electrical cables in the loft. These properties were built to the building regulations required for the National House Building Council 10-year warranty. None of these have burn down!

:rolleyes:

Hi...your experiences (or even mine;) ) do not provide an representative sample of all residential lofts in the UK. The OP should seek the advice of a professional and not rely on the opinions presented here on an anonymous internet forum. I provided the link to demonstrate the potential impact of loft insulation on wiring eg. potential requirement for derating of cable dependent of the actual location of the cable and its use. Before we insulated our loft we asked my OH's mate for his professional opinion as an NICEIC domestic electrical contractor...he gave us advice based on the particulars of our loft/wiring.

HTH

Canucklehead

CheekyMonkey

The simple solution is not to cover the wiring - why take the chance?
It's common sense really, so I dont understand the mixed responses. Just lift the wiring above the current or replacement insulation and leave any junction boxes completely clear. It's also easier to locate any problems in future.

I've recently replaced the existing fibreglass insulation in my old house (what a filthy job that was) with a product called 'SpaceBlanket' from B&Q. Not the best insulation you can get but more than adequate. The instructions on the product specifically state that you should not cover wiring in the event that it could overheat.

I agree that new houses should be fine, due to better wiring regulations, but in old houses it's just not worth taking added risks !!!

We can all drive about without a seatbelt saying that we've never had an accident, BUT I would much prefer to take precuations than leave things to chance.

jimbo_the_jetset

CheekyMonkey wrote: »

The simple solution is not to cover the wiring - why take the chance?
It's common sense really, so I dont understand the mixed responses. Just lift the wiring above the current or replacement insulation and leave any junction boxes completely clear. It's also easier to locate any problems in future.

I've recently replaced the existing fibreglass insulation in my old house (what a filthy job that was) with a product called 'SpaceBlanket' from B&Q. Not the best insulation you can get but more than adequate. The instructions on the product specifically state that you should not cover wiring in the event that it could overheat.

I agree that new houses should be fine, due to better wiring regulations, but in old houses it's just not worth taking added risks !!!

We can all drive about without a seatbelt saying that we've never had an accident, BUT I would much prefer to take precuations than leave things to chance.

Exactly, I was going to write something similar but you beat me to it

RAndrews_2

Bexm wrote: »

Hello

We are in the process of laying some more loft insulation in the hope that it may keep our freezing house a little bit warmer but we have a question that I thought one of you may be able to help with?

There was already some insulation laid but it looks like there were mice at one time as half of it has gone and the rest is shreaded. There is a small junction box with about 5 wires coming out of it screwed to the floor that powers the lights in our bathroom and various other things.

My fiance says its fine to lay the fibreglass over this, as it looks like the previous stuff was, but I am not so sure as I think its a fire hazzard?

What should we be doing?

Thanks in advance for your help.

Bex

Hiya!
My work title is NICEIC Domestic Installer - Priciple Duty Holder & Qualified Supervisor Part P for ******.
If I were to rewire your loft and cables passed through 100mm + thermal insulating material the cable size used would take account of this.

BUT! I'm not sure if there's any law or regulation which states you can't add 300 or 600mm of insulation to your loft as the house owner.

The latest I.E.E Electrical Regulations are specific with what us electricians must do, hence "yes" to a fire hazard... Just think - the Government are providing grants for home insulation... I wonder if the resulting increased fire hazard is taken into consideration.

And such must be an hazard, otherwise why would the Institute of Electrical Engineers add regulations covering such?

Me

Errata

My ex-council - now Housing Association - property has just been re-roofed and new loft insulation installed. The insualtion has been laid over all cabling in the roof space so if this is illegal I'd be very grateful if someone could give me a link to the bit I need to quote to the HA?

27col

Whilst I agree, that ideally, the wiring should not be covered by insulation, the fact is that with the best will in the world, a lot of installations do not have enough extra length of wire to allow the cables to be moved. In fact when I recently installed new light fittings in my son's 10year old house there was so little free cable that it was almost impossible to get enough length to connect up the new fittings.
Any wiring that I did as an electrician had plenty of extra cable, maybe not the prettiest installation, but capable of being worked on and modified, if necessary. It is true to say that lighting circuits in the loft are capable of carrying much higher currents than they actually have to, and are extremely unlikely to even get a little warm. In my house it is rare for there to be more than one or possibly two, low energy lamps on upstairs. Obviously some people have a greater usage, but low energy lamps are the way forward.
Cables feeding showers are quite likely to get warm as they are carrying a fixed and large current. They could easily get hot if covered by insulation.
Actually, it would be very easy to rewire the loft wiring if there was any doubt as to its safety. But I doubt whether it has been done in many houses.

Errata

Cables feeding showers are quite likely to get warm as they are carrying a fixed and large current. They could easily get hot if covered by insulation

Yikes - mine are ! There's also one for the extractor fan - dunno how much current it uses but it sounds like Concorde warming up when it's on.

Faith1_2

I understand that the new regulations will require that insulation will not be laid over wiring in the loft.