On 16 Sep, 13:06, Tim S wrote:
Jon coughed up some electrons that declared:

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.

Hi Jon,

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.

Thanks for your response Tim.

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

Thanks,

Jon