Adding outlet to wall with batt insulation – GreenBuildingAdvisor

Yes, you can do that. Cut the hole for an “old work” cut-in box, then use a serrated knife to cut a hole in the insulation roughly the size of the back of the box. You’re unlikely to get a perfect fit, but you can at least prevent the box from “dimpling” in the insulation at that spot.

The bigger issue is the wire messing up the insulation. If the electrician has to fish a wire in the wall with the batts, the fishing operation is going to mightly mess up the batt in at least the one stud bay where the box is. There isn’t really any way around that. About the best you can do is to tape over the hook on your wire fishing tool to limit how much it “grabs” the insulation as you pull the wire through.

Fishing wire inside insulated walls just sucks. No way around it.

Bill