This Korean Industrial Standard specifies normal watt—hour meters independently used not in combi-nation with instrument transformers in single—phase 2—Line, single—phase 3—line, and three—phase 4 —line circuits
KS C 1212-1989 history
1992KS C 1212-1992 ALTERNATING CURRENT WATT-HOUR (ELECTRICAL ENERGY) METERS (TYPE-IV WHOLE CURRENT METERS)
1989KS C 1212-1989 Korean Industry Standard AC—Current Watt—Hour Meter (For Type—IV Direct Connection)