30 CFR § 75.900-4
Testing, examination, and maintenance of circuit breakers; record.
The operator of any coal mine shall maintain a written record of each test,
examination, repair, or adjustment of all circuit breakers protecting low-
and medium-voltage circuits serving three-phase alternating current
equipment used in the mine. Such record shall be kept in a book approved by
[35 FR 17890, Nov. 20, 1970, as amended at 47 FR 14706, Apr. 6, 1982; 60 FR
33719, June 29, 1995]