2018UNE-EN 62053-21:2003/A1:2018 Electricity metering equipment (a.c.) - Particular requirements - Part 21: Static meters for active energy (classes 1 and 2)
2003UNE-EN 62053-21:2003 Electricity metering equipment (a.c.) - Particular requirements -- Part 21: Static meters for active energy (classes 1 and 2)