Connector receptacle, with switch, 30 amp, 450 VAC, 3 Phase with ground, watertight. Consists of a 4 pole (3 phase plus ground) receptacle mounted in the cover of a 4x7 (nominal) brass enclosure. Power to the receptacle is controlled by a 30 amp 450 VAC switch which is interlocked with the protective cap or the mating plug to prevent engaging or disengaging the plug or installing or removing the cap while the switch is in the "ON" position. This device is watertight to a depth of 3 feet with the cap or mating plug installed. Normally used to provide power to portable welding machines or submersible pumps. Per MIL-R-2726/19, Military P/N M2726/19-001. NSN 5999-00-879-1519. Mates with Symbol 717.1 plug per MIL-R-2726/3. Electrical connections are made directly to the terminals on the switch which have #10 screws. The ground connection to the box is a #8 screw. The receptacle assembly is a Symbol 758.2 and the cap assembly is a Symbol 1142.1.