This specification applies to indoor 3-pole air-break circuit-breakers for three phase a.c. systems of voltages of 415 V to 11 kV but excludes circuit breakers up to 660 V having breaking currents less than 21.6 kA. This Standard does not apply to combinations of circuit-breakers and fuses in series, contactors or to switchgear in flameproof enclosures. Information regarding frequency of operation for normal load and motor switching is given in Appendix C. Where the duty includes frequent operation at short intervals the manufacturer should be consulted. No requirements for enclosures are given.
| Edition : | 1st |
| Number of Pages : | 0 |
| Published : | 01/01/1967 |
