A box for receiving an electrical device and preserving the vapor barrier, which may include a wall defining a cavity having an opening, the wall having a perimeter proximate the opening, a base, a first pair of flanges disposed on the perimeter attachable to a first surface of a structural member of a building and a first surface of a second structural member, a pair of flaps disposed on the perimeter, a second set of flanges disposed on the flaps for attachment to the first and second structural member, the second flange attachable to the first surface of the structural member or to a second surface of the structural member different from the first surface when the first flange is attached to the structural member, and a third set of flanges disposed on the flaps. A method of use thereof includes installing the box between two structural members such that the two structural members, the base, the perimeter and the flaps create a cavity for the installation of a low voltage electronic device.