Abstract: An expandable while-in-use cover includes: a cap having a pair of cap side walls, a first cap end wall, a second cap end wall and a top wall, which define a cap opening and a cap interior; a base having a pair of base side walls, a first base end wall, a second base end wall and a back wall, which define a base opening and a base exterior, wherein the base side walls and base end walls correspond to the cap side walls and cap end walls and wherein the cover is adapted to slidably and/or telescopically receive the base; a first and second prong on the interior of each of the cap side walls near the first and second cap end walls; a first and second slotted track on the exterior of each of the base side walls near the base end walls, wherein the first slotted track of each base side wall is adapted to receive the first prong of each cap side wall and the second slotted track of each base side wall is adapted to receive the second prong of each cap side wall; and an aperture in the back wall for accessing an ele