High-Voltage Switchgear and Controlgear. Gas-filled wrought steel enclosures|Documents, Welded joints, Dimensional tolerances, Designations, Defects, Electric enclosures, Certification (approval), Type p protected electrical equipment, Welding, High-voltage equipment, Protected electrical equipment, Marking, Test specimens, Inspection, Switchgear, Electric control equipment, Approval testing, Wrought alloys, Form tolerances, Design, Acceptance (approval), Non-destructive testing, Steels, Electrical insulation devices, Pressure regulators, Performance testing, Enclosures, Fusion welding