ECN Forum Forums Code Related Discussion NEC & other Code issues Vapor Barrier Boxes

Nope can't say I've seen or heard anything about them.
When I built my house,I used caulk to seal the boxes on the exterior walls. I caulked the holes the cables entered the box and any unused "knockouts". I caulked any penetrations where a cable was stuck out through the sheathing also. I did all this prior to installing my insulation. I have no air leaking in through my receptacles and switches.