This standard applies to enclosed low-voltage ac power circuit breakers as described in American National Standard for Low-Voltage AC Power circuit Breakers Used in Enclosures@ C37.13-1973 (IEEE Std 20-1973)@ except that the circuit breakers discussed in this standard incorporate current-limiting fuses as an integral part of the circuit breaker. The entire device thereby becomes capable of interrupting short circuit currents up to 200 000 Arms and may be applied on circuits where the available short-circuit current does not exceed that amount.