Hubbell Wiring Device-Kellems mechanical interlocks are used for preventing haphazard connections and breaking / making circuits under loads. These interlocking devices feature plugs which cannot be removed till the switch is turned Off and a lockable handle meeting OSHA lockout / tagout regulations. These UL listed & CSA certified interlocks have shaft seals made of neoprene to provide high thermal stability and are capable of being operated at voltages up to 600VAC (RMS). Choose from a wide range of these mechanical interlocks, available in 2, 3 & 4 pole configurations Raptor Supplies also offers circuit-lock mechanical interlocksfeaturing Plug-Check mechanism for detecting the presence of plugs.