Hubbell Wiring Device-Kellems HBL420MI12W Unfused Watertight Mechanical Interlock Device, 120/240 VAC, 20 A, 3 Poles, 4 Wires

Hubbell® revolutionary Circuit-Lock® interlock incorporates the disconnect switch and receptacle in one compact, non-metallic and economical unit. Removing the plug and locking it out provides a visual means of verifying equipment has been disconnected. All Circuit-Lock® mechanical interlocks can be locked out as a method of compliance with the OSHA lockout tagout regulation. The switch cannot be turned ON until the plug is completely engaged and the plug cannot be removed until the switch is turned OFF. At the same time, it eliminates the possibility of making or breaking the circuit under load or making a casual or ''lazy'' connection. The non-metallic enclosure can be connected to the metallic conduit and not interfere with the ground continuity.