Siemens GIS is interlocked by electromechanical equipment. These interlocking facilities are located in the local control cabinet of each bay. They provide reliable protection against any potentially harmful mal-operation of the switchgear. The following functionality will typically be provided, while the exact design will be formed through the secondary design process as part of the schematics for the LCC:- The operator must be forced into the only safe and logical sequence to actuate circuit-breakers, switches, disconnectors and earthing switches.- The actual, completely closed or completely opened position of all switching devices must be checked before and after each move.- Implementation of logic checks and issuing the resulting signals ENABLE or BLOCKED for the switching device.- Manual local operation and automatic remote operation for all essential functions.- Local emergency unlocking equipment via safety key switch under full responsibility of the operator.