The normal voltage range of household cables is 198V~235.4V.
This range is determined according to Article 54 of the "Power Supply Business Rules" of the national standard, which takes into account the dynamic characteristics of the power system and the difference in power load during the day and night. Due to the impedance of the power supply line, the voltage will be reduced during the transmission process. Therefore, in order to ensure that the terminal voltage is within the allowable deviation range, the voltage at the power supply head is usually set between 220V and 235.4V. In addition, the voltage fluctuation range standard for residential electricity is +7%, -10%, which means that the voltage of residential electricity is qualified between 235.4V and 198V. If the voltage at home is lower than 220V, this is usually normal. The key is to check whether the degree of voltage reduction exceeds the lower limit of the voltage fluctuation range. If it exceeds this range, measures may need to be taken to avoid affecting the normal use of home appliances.