A Brief History of Metal-Clad Switchgear [History]

Metal-clad switchgear has been a workhorse of medium-voltage distribution systems, both industrial and utility, for nearly 80 years. While changes in this equipment have not been nearly as frequent as in some other types of equipment, such as variable-frequency electronic drives, during that period, there were many developments in the design and application of metal-clad switchgear. However, since it has a normal service life of 40 years or so, rapid change in equipment design is not demanded by the users.