switchgear refers to voltage of 1 kv and above potestatem system cursus amet ac velit ac switch instructis apparatu bellicopraesertim in systematis electricis adhibitis (including vim herbarum, substationum, transmissionis et distributionis linearum et inceptis industrialibus et fodiendi et aliis utentibus) de potestate ac tutela, sicut etiam in operatio of the power grid need to be part of the electrical equipment or lines into or out of operation, Can also be in the power equipment or line defect when the fault part from the power grid quickly cut, so as to ensure the normal operation of the virtus eget sine culpa pars et salus armorum, operandi et sustentationis personas.