Metal-Enclosed Switchgear: This is Switchgear that complies to ANSI C37.20.3. The construction is such that the bus is open and there are few if any barriers between the bus and cable sections. Typically the bus is not insulated, and boots are not required. This is a very cost effective construction for applications that seldom require access to the inside of the Switchgear, and for infrequent operations. Typical examples of Metal-Enclosed products are Load Interrupters, Medium Voltage MCC’s, Utility Metering Sections, pull sections, hybrid designs with LI switches in series with a Vacuum Circuit Breaker.

Load Interrupter: This is a Metal-Enclosed MV device that essentially functions like a large switch to open or close allowing power to be interrupted or allowed to flow. This is the least expensive method of controlling the power in a MV circuit. A couple of key limitations apply to the LI switch: 1) It is not designed to interrupt a fault current. 2) The opening and closing can take much longer than a VCB. The Switch is designed to have a limited number (200 no-load, 10 to 20 with load) of opening and closings. The amperages are limited to 1200A maximum.