A housing includes at least one openable cover and at least one adjacent cover. The at least one openable cover swings on a hinge to separate an interior of the housing from an exterior of the housing. The at least one openable cover has a first side edge on a side of the hinge. The at least one adjacent cover is adjacent to the at least one openable cover. The at least one adjacent cover has a second side edge neighboring the first side edge of the at least one openable cover across a gap. One of the at least one openable cover and the at least one adjacent cover includes at least one projection projecting into the gap and another one of the at least one openable cover and the at least one adjacent cover includes a recess that accommodates the at least one projection in the gap.