Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Replies 21 replies
  • Subscribers 40 subscribers
  • Views 746 views
  • Users 0 members are here
Options
You may also be interested in

Insulation and thermal bridging and an EV charger

JohnE

The situation is a garage being converted into a TV room

External wall with batten attached which is to be insulated with 75mm PIR insulation and plaster boarded
Stud is only 70mm!!

Picture attached...

The house CU is high up on the wall. the tails ran down the internal garage wall to the outside meter box
A second CU was mid way down the wall feeding  an external EV charger, the tails of which also went to the external meter box

The tails were in plastic conduit surface mounded.

Since the tails (no RCD protection)to both boards are to be hidden by the plasterboard, I though best to put in two lengths of earthed metal conduit (50x50)
The 10mm feed to the 7kW charger is clipped to the batten.

The owner is doing the batten and insulation.
I am concerned about insulation being near my cables and trunking


I presume the trunking it self will be a break in the insulation so could be a thermal bridge?

Could you run the insulation up to the trunking or should they be a gap.

cables clipped along the batten how far should they be from the insulation,
I would like to leave about a 50mm gap? but this will cause this thermal bridge issue I believe?

Also say if  a 2.5mm  socket radial (fused to 16A) was ran through the batten and against the concrete block 
with insulation over it. What installation method would you consider that. I presume these soft concrete blocks have some insulation factor.
Will they be much of a heat sink?

I am concerned about the EV cable really as a continuous load in this stud work. Its has a bit of extra capacity as 10mm2 for a 7kW charger.

How can the wall be adequately insulated, without bridging and the cables be safe?

Thanks

Parents
  • 0

    Personally I prefer not to run cables within thermal insulation, but pick a side (inside or outside) and run them to that side as far as possible. A trick I've used with 75mm celotex is to have "chases" where strips of 50mm rather than 75mm board is used - which gives a 25mm void behind the plasterboard (but still "inside" of the insulation) for cables and back boxes. Foil tape over the insulation board joints maintains the vapour barrier.

    I haven't quite pictured the insulation board/studs/battens arrangement - I'm guessing the 70mm studs will be packed off the walls by 5-10mm and insulation boards between? (Trying to squeeze 75mm celotex/kingspan board into a 70mm gap by screwing the plasterboard down on top of them would be a disaster - PIR/PUR boards might feel a bit soft when pressure is concentrated over a small area like a finger, but it takes an awful lot of force to squeeze them over larger areas - and if there's a gap between the studs and plasterboard, the screws heads will pop though the plaster when the studs shrink and then expand with the seasons.

    I'm not sure I'm making sense of the EVSE cable route - without anything visible to mark its route it looks like it would be outside zones - which would be a no-no unless you can ensure its more than 50mm deep, regardless of 30mA RCD protection.

       - Andy.

Reply
  • 0

    Personally I prefer not to run cables within thermal insulation, but pick a side (inside or outside) and run them to that side as far as possible. A trick I've used with 75mm celotex is to have "chases" where strips of 50mm rather than 75mm board is used - which gives a 25mm void behind the plasterboard (but still "inside" of the insulation) for cables and back boxes. Foil tape over the insulation board joints maintains the vapour barrier.

    I haven't quite pictured the insulation board/studs/battens arrangement - I'm guessing the 70mm studs will be packed off the walls by 5-10mm and insulation boards between? (Trying to squeeze 75mm celotex/kingspan board into a 70mm gap by screwing the plasterboard down on top of them would be a disaster - PIR/PUR boards might feel a bit soft when pressure is concentrated over a small area like a finger, but it takes an awful lot of force to squeeze them over larger areas - and if there's a gap between the studs and plasterboard, the screws heads will pop though the plaster when the studs shrink and then expand with the seasons.

    I'm not sure I'm making sense of the EVSE cable route - without anything visible to mark its route it looks like it would be outside zones - which would be a no-no unless you can ensure its more than 50mm deep, regardless of 30mA RCD protection.

       - Andy.

Children
No Data

Community Rules & Guidelines