Electricity metering (AC) - Tariff and load control - Part 21: Particular requirements for time switches (IEC 62054-21:2004 + A1:2017); German version EN 62054-21:2004 + A1:2017
电能计量(AC).电价和负荷控制.第21部分:计时开关的特殊要求(IEC 62054-21-2004+A1-2017);德文版EN 62054-21:2004+A1:2017