US Patent 7253356 Waterproof structure of junction box

A waterproof housing of a junction box has at least one vent piece penetrating through a wall of the housing for ventilation of the junction box. The vent piece has an inner wall formed with a baffle projection to prevent invasion of a splashing water. The waterproof housing has a plurality of the vent pieces. The waterproof housing also has a drain hole provided in the housing. The vent piece has an inside opening positioned higher than the drain hole when the junction box is mounted at a usage position. The baffle projection is positioned at an axial inner end portion of the vent piece. The vent piece has a central axis inclined relative to an invasion direction of an expected splashing water.