The cutouts for every switch, outlet, and light fixture need to be sealed before the drywall is hung.
A foam Energy Block provides an efficient way to seal all the little holes in an electrical box. Before installing the drywall, the author will apply a thick bead of caulk to the stud and the block’s wide forward-facing edge to seal the outlet perimeter.
Recessed lights in an unconditioned attic can be sealed at any time before insulation with site-made boxes.
Recessed lights in a cathedral ceiling must be addressed before the lid is hung. Here, the author surrounds a fixture with a box made of foil-faced foam.
Taping the edges of a fixture is easier than applying caulk, but will do nothing to seal holes in the fixture itself.
All wire penetrations through framing next to unconditioned spaces must be sealed before drywall. This applies to penetrations in exterior walls as well as interior partitions.
To seal the drywall perimeter, a helper applying sealant needs to stay in front of the crew hanging the panels.