Abstract: An enclosure for terminal blocks for interconnecting conductors of multiconductor cables includes provision for two or more terminal block modules. A lid is pivotably hinged to a box-like base section, with the base section including front and rear walls extending upwardly from a floor, and side walls extending downwardly from a transverse section of the lid into the open regions between the front and rear walls of the base section when the lid is pivoted to its closed position. When the enclosure is mounted vertically the lid is pivotable to an open position overcentered to remain open unassisted. The side walls include ribs having projections which engage upper edges of ridges extending upwardly from side edges of the floor between the front and rear walls, thus camming the lower edges of the side walls inwardly tightly against outwardly facing surfaces of the ridges for sealing.