Electricity metering (AC) - Tariff and load control -- Part 21: Particular requirements for time switches (IEC 62054-21:2004 + A1:2017) (english version)
91.140.50 Electricity. Including electric energy meters in buildings, emergency electrical supplies, etc. / Системы электроснабжения. Включая аварийное электроснабжение и т.д.
