This standard applies to three-pole units for public and industrial distribution systems which are functional assemblies of switches including switch-disconnectors and current-limiting fuses and thus able to interrupt:
- any load current up to the rated breaking current of the switch;
- any over-current up to the rated short-circuit breaking current of the combination by which automatic interruption is initiated.
This standard applies to combinations designed with rated voltages above 1 kV and below 52 kV for use on three-phase alternating current systems of either 50 Hz or 60 Hz.
IEC 60420:1973 history
1990IEC 60420:1990 High-voltage alternating current switch-fuse combinations
1970IEC 60420:1973/AMD3:1978 Amendment 3 - High-voltage alternating current switch-fuse combinations and fuse-circuit-breaker combinations
1970IEC 60420:1973/AMD2:1977 Amendment 2 - High-voltage alternating current switch-fuse combinations and fuse-circuit-breaker combinations
1970IEC 60420:1973/AMD1:1975 Amendment 1 - High-voltage alternating current switch-fuse combinations and fuse-circuit-breaker combinations
1970IEC 60420:1973 High-voltage alternating current switch-fuse combinations and fuse-circuit-breaker combinations