BS EN 62040-1. Uninterruptible power systems (UPS). Part 1. General & safety requirements for UPSElectric power systems, Uninterruptible power systems, Electrical equipment, Power control (electric), Electronic power supplies, Electric convertors, Electric cells, Rectifiers, Protected electrical equipment, Alternating current, Direct current, Voltage, Low-voltage equipment, Safety measures, Electrical safety, Electrical testing, Occupational safety, Operators (personnel), Equipment safety,