30 CFR § 75.900-3
Testing, examination, and maintenance of circuit breakers; procedures.
Circuit breakers protecting low- and medium-voltage alternating current
circuits serving three-phase alternating current equipment and their
auxiliary devices shall be tested and examined at least once each month by a
person qualified as provided in §75.153. In performing
such tests, actuating any of the circuit breaker auxiliaries or control
circuits in any manner which causes the circuit breaker to open, shall be
considered a proper test. All components of the circuit breaker and its
auxiliary devices shall be visually examined and such repairs or adjustments
as are indicated by such tests and examinations shall be carried out
immediately.