​This Standard applies to all oil circuit-breakers for single-phase and three-phase A.C. systems, except oil circuit-breakers up to 660 volts intended for use in those electrically remote parts of a system where marked asymmetry of fault-current cannot occur and where the restriking-voltage conditions are not severe. Further, it does not apply to combinations of circuit-breakers and fuses in series, oil isolators, oil selectors, oil circuits frequently at short intervals (e.g., starting-switches), neither does it include the additional requirements necessary in connection with flameproof switchgear. Those characteristics of oil circuit-breakers which are associated with resistance switching are not completely dealt with in this standard.