Abstract: There is a commercial wiring system and method for wiring, which is designed to increase the speed of installation of wiring devices. In one embodiment of the invention there is a bracket which is designed to receive an adapted wiring box. This bracket has tabs for fixing to a wiring box to form an electrical box. The bracket can be coupled to another bracket that is adjustable in length and includes at least two legs, with a first leg being slidable in position in relation to a second track. A first set of tracks in the first assembly is designed to receive the second set of tracks in the second assembly in a telescoping or nested manner. The adjustable electrical box assembly can include a box section, a mounting plate and a mud ring or plaster ring.