... .With DC immunity upon IEC 62053-21 standard (current transformer, precision CT,transformer) Current Transformer NRC05 CharacteristicsValuesOperating frequency50/60HzOperating temperature-25 ~ 75oCRelative humidity80 ... damage by 3000V for 1 min.Insulation resistance> 50MΩ ( current transformer, precision CT,transformer) Current Transformer with DC immunity NRC05