Electricity metering (AC) - Tariff and load control -- Part 21: Particular requirements for time switches (IEC 62054-21:2004 + A1:2017) (english version)
Electricity metering (a.c.) - Tariff and load control -- Part 11: Particular requirements for electronic ripple control receivers ( IEC 62054-11:2004 + A1:2016) (english version)