BS 05760-10.3-1993 (1999) IEC 1070-1991 ๐ BS 05760-10.3-1993 (1999) IEC 1070-1991 ๐ Scientific ๐ 1999
BS 05760-13.3-1993 (1999) IEC 605-3-3-19 ๐ BS 05760-13.3-1993 (1999) IEC 605-3-3-1992 ๐ Scientific ๐ 1999