Metal-clad switchgear is an assembly that contains all parts within a grounded metal enclosure. Secondary control devices and their wiring are isolated from all primary devices by grounded metal barriers or shielding. Major parts of a primary circuit such as circuit breakers and transformers are also isolated by grounded metal barriers.
The circuit breaker is removable and equipped with self-coupling primary and secondary disconnecting contacts. It has a disconnecting mechanism to move it from the connected to the disconnected positions. All buses, connections, joints, and connections to joints are insulated, and the stationary structures consist of self-supporting steel frames.
Metal-clad switchgear should not be confused with metal enclosed switchgear where the individual components are not isolated from each other even though enclosed in a protective metal cabinet.
