Abstract: There is disclosed a base member for holding, without screws, a printed circuit board having conductive traces and electronic components and which can fit into an electric outlet box. The base member has walls which define a cavity where at least one wall of the cavity has a rib, the top of which functions as a stop for the printed circuit board. A cap having snap features adapted to engage the walls of the cavity restricts removal of the printed circuit board when snapped into position on top of the printed circuit board. The cap conceals the electronics on the printed circuit board and has at least one rib on its bottom surface to apply pressure to the printed circuit board assembly to help hold it in place. An aperture in the cap provides access to a pin header which is electrically connected to the printed circuit board. A screw terminal block is provided to connect the terminals on the pin header to a sensor.