Expanding foam behind CU

[Jon]

Hi,

Our consumer unit is on an external wall in the downstairs toilet above the window and is very draughty, which makes the room cold in the winter. I want to seal it up to prevent any draught's coming through.

I was thinking of boxing it in draught sealing it (with a door for access), but the missus' step-father suggested taking the front off the CU and squirting some expanding foam in the void behind it to seal it all up from there. It'd be much less hassle to do this.

Is this an ok thing to do? I've read that expanding foam can be corrosive to cable insulation!? Not sure if it's an urban myth or not.

Thanks,

Jon

[Tim S]

Jon coughed up some electrons that declared:

I wouldn't do that. Apart from any possible reaction between the foam and the PVC, you'll be adding thermal insulation around the cables (already bundled) and you'll make it very difficult to remove of add cables later, assuming the cables go through the void you mention (if not, what's the void for).

Not to mention there are live cables in the CU, even with it's isolator in the off position - is liquid foam conductive?

Go with your original idea is my advice, but make sure the cupboard is either removable or big enough to allow working inside the CU.

Cheers

Tim

[Jon]

Thanks for your response Tim.

Your reasoning is sensible and I will go with the boxing-in.

Thanks,

Jon

[meow2222]

not even remotely sensible. You're filling an electrical item that requires a little airflow to cool the cables, and often fuses, with an insulator. Not just that, but its flammable. And not only that, but it will prevent any future work in the CU short of scrapping it. And not only that... but it expands with great force as it sets, likely buggering the CU beyond saving.

If you have draughts, fix the hole in the wall or window, boxing the CU in isnt a very good answer.

NT

[Andrew Gabriel]

You can buy little sand-bags to stuff in wiring holes like this from electrical wholesalers. It's required in buildings where the hole goes through a wall which provides fire protection. They can be removed to thread new cables through. You might be able to improvise with some dry sand and socks (without holes in them ;-)

[George (dicegeorge)]

hmmm.. if i go to B&Q and ask for little sandbags theyll look at me funny again, anyone got a link or number for them please? [g]

xxxxxxxxxxx

[Owain]

(Again?)

intumescent cable seal bag or pillow

[Andy Wade]

Go to an electrical wholesaler and ask for intumescent pillows.

[George (dicegeorge)]

I've taken advantage of the dry weather and removed 2 broken opening metal windows, they're in the best room, the Snug, so how shall i paint them - not water based paint!

Hammerite - what's the difference between smooth and satin and hammered, which would look best on an old victorian house?

'm scraping off the paint and putty and car body filler, going to Leominster or Hereford tomorrow to buy paint and solvent etc, any recommendations please?

[g]

[George (dicegeorge)]

Should i paint it before or after i put the glass in?

Should i fit the window back into its frame before i put the glass in in case its been bent out of square?

Should i clean it with anything after scraping most of the paint off with a blunt chisel?

[Tim S]

George (dicegeorge) coughed up some electrons that declared:

I'd prime all of it well before putting glass in. Then you know there are no bits exposed to the elements. Putty sticks fine to primer. Undercoat and gloss after glass.

Are these iron windows? It would be hard to bend them out of true I would have thought. I'd put the window in the frame before glazing (are there fixing screws that are obscured by the putty? Also the stresses of fitting the window might break the glass.)

If what's left is sound, just prime it. HTH

Tim

[Dave Baker]

Hammerite is ok as a one-coat quick fix on bare metal and I've used a lot of it on engines I've built for customers over the years but it doesn't cover that well on smooth metal (you get streaks) and it's tricky to apply second coats. You definitely don't want hammered finish which has bits of metalflake in it and is used on engine blocks, industrial machinery and castings to give a sort of mottled effect. Smooth is the normal choice for domestic use. I've never tried (or even heard of) the satin. It also needs its own thinner/solvent to clean brushes which is a pain. White spirit won't do the job. Although I still use it, mainly because I have plenty left over, it's not all it's cracked up to be IMO.

To be honest I'd go for Dulux Metalshield zinc primer followed by two coats of Dulux Metalshield Gloss topcoat. It's designed for exactly that job and should see you good for another ten years or so. A mate of mine always used to say "when decorating never skimp on the quality of the paint". I've failed to follow his advice a couple of times and always regretted it. Pick a good brand (they've spent the money on R&D making sure it works) and slap plenty of it on the job. Better to do it once properly than twice badly.

[meow2222]

All depends what state its in. If the paint is mostly sound, no need to scrape off. If OTOH the whole thing is a terrible mess, a wire brush in an angle grinder would strip everything off, rust included.

Usually ordinary household gloss is used. Car paints last much better on steel & iron, but cost more initially. Personally I dont recommend hammerite, it pinholes badly IME.

NT

[George (dicegeorge)]

there was no zinc primer in leominster, and only a 5 liter bucket for about £90 in hereford, i bought some grey dulux metal primer and spent many hours scraping the old paint off, with titchy filing at the intricate handles, and have just painted it with the primer, so hopefully i can put the glass in tomorrow and put them in so burglars cant hop in! (did you get that safe open lads?)

[george]