This Korean Industrial Standard specifies load break-switches (hereinafter referred to as "break switches") with rated current not more than 600A used for three-phase channel of nominal voltage of 3.3kV or 6.6kV and frequency of 60Hz, and high-voltage alternating current switch-fuse combinations operated manually or by electric power.
Remarks 1. Three-phase break switch can be used without hindrance for single-phase channel.
2. The scope shall not be applied to break switches for capacitor, electric channel and electric motor used very often, however, the application is adaptable as agreed between maker and user if the application frequency of the break switch is within the limit of this standard.
3. Current switch fuse shall conform to KSC 4612.
4. Normative references to this standard shall be as follows.
KS C 4509 AC Load Break-Switches with Tripping Device for 3.3kV or 6.6kV KS C 4511 AC Load Break Switches for 3.3kV or 6.6kV KS C 4612 High-Voltage Current-Limiting Fuses
5. The international standard corresponding to this standard shall be as follows. IEC 420 - 1990 High-Voltage Alternating Current Switch-Fuse Combinations