Mining type flameproof supply and control units for use on systems up to 1100 V. Specification for air-cooled lighting transformer units|Type d protected electrical equipment, Temperature-rise limit, Electric control equipment, Cable junctions, Type testing, Coal mining, Isolator switches, Short-circuit current tests, Mining equipment, Lighting equipment, Air-cooled systems, Overcurrent protection, Electrical protection equipment, Rated frequencies, Clearance distances, Rated current, Bus-bars, Name plates, Earthing, Leakage paths, Design, Electric enclosures, High-voltage tests, Performance testing, Environment (working), Rated voltage, Electrically-operated devices, Protected electrical equipment, Marking, Single-phase transformers