7 points
I would use fire block since normal expanding foam is flammable. If I could get behind it, I would see if the hole was excessively large and if so, cut a piece of OSB to fit the space with a hole the correct size in it. Then I would bisect the piece of OSB (making sure to bisect the hole) so that I would be able to get it around the cables and refrigerant line. If the hole isn’t excessively large, fire stop caulk the penetration and insulate the best you can.
7 points
I’d pack some stainless steel wool around it before doing the expanding foam. This will prevent rodents from chewing through it, which they can do to the foam.
They make rodent-blocking foam but I trust the steel wool more
5 points
4 points