Expandable while-in-use electrical box cover

An electrical box cover including a base having a back wall perimetrically bounded by an upwardly extending side wall. The back wall having an opening for receiving an electrical device. A lid pivotally connected to the base. The lid having a lid plate with an opening that is defined by a collar. A housing having a front wall and a plurality of contiguous side walls extending therefrom to a distal edge to define a housing interior. The housing has a flange extending from the side walls and is slidably disposed in the lid opening and moveable between a retracted and extended position with respect to the collar. A plurality of lugs can extend inwardly from the collar and the flange engages the lugs when the housing is in the extended position.