Insulation and power cables

[Kaymo]

Hi,
Couple of questions relating to insulation and power cables, grateful for any advice.

I have pulled down the old plaster in a room and I am insulating internally, but at the section in the picture there are a large number of power cables running together from the meter/consumer unit cupboard so I have just cut and stuck a couple of bits of insulation on either side to leave a channel for the cables. Does the gap I have left seem enough for this number of cables/could I get away with less? Ideally I would not have a completely uninsulated cold bridge here, but I also know I can't bury cables in insulation. Would I get away with 10mm of PIR between the cables and the plasterboard, given that the other side of the cables is an uninsulated external stone wall or would that be a no-no?

Also insulating between joists in the floor and so cable currently through sub-floor void will have to go through 90mm of PIR. Is it ok to have it snug between the cable and the outside stone wall, or is it advisable to leave a gap around the cable?

 

[Wayners]

I think cables can get warm so don't sandwich in insulation.
I think they put in cut channel on the front of insulation vs under it for this reason.
I've seen YouTube videos on using kingspan and running cables.
That's all I know..
How about some plastic trunking? You can only get big stuff from electrical trade centres

 

[Kaymo]

Hi Wayners,
It was me who put the insulation in there and left a gap around on either side. These cables were previously buried under lath an plaster and what's behind them is the very old plaster direct to stone that would have been the finish before the lath and plaster went on. I've pulled the lath and plaster off and I am insulating the wall then putting plasterboard over it.

I have left the plasterboard off this section until I can learn more about how close I can get to it or how much space I need around it, especially as this is nearly every cable in the house coming out of the top of the consumer unit so it definitely can't be completely buried in insualtion. I could just run the plasterboard over the top and it would be in a similar state to the way it was before, but wanted to get some advice first.

 

[Wayners]

Rock wool around cables to insulate maybe?
Stick plasterboard over with foam or polymer grab mastic

 

[Kaymo]

Thanks Wayners, appreciate the response but I am fine on how to attached the plasterboard, and rockwool around the cables is still burying them in insulation.

I'd hoped one of the electricians would be along to comment on whether there was any guidance in this situation.

 

[Kaymo]

Any electricians or those knowledgeable on electrics able to comment on this?

I have done a fair bit of searching to get some guidance on this but the advice on dealing with insulation and electrical cables seems really vague, which is surprising considering that almost all houses now have electrical wiring and insulation. I have seen some things about individual cables saying leave double the width of the cable and everything between "it'll be fine" to "thou shalt not" go within a hundred miles of cable with insulation.

Even where I see what looks like specific guidance about insulation I have seen generic terms like "100mm insulation", which is strange when you consider that 100mm of one type of insulation has the same insulating effect as 200mm of another type.

I'm less concerned about the individual cables coming through the floor because the cable run through the PIR very short and I can use a short bit of conduit to keep an air gap around them, but the mass of cables in the pic is a bit more concerning. On one hand I suspect if I left the same amount of air space either side as shown in the pic and put 10mm PIR over the top before the plaster, then this would help eliminate the cold bridge but is not likely to insulate too much as the cables are up against plaster hard on to a cold stone wall. On the other hand this cable run must include higher current carrying cables for the shower, cooker, hob etc.

Am I over thinking this?