30 U.S. Code § 866 - Trailing cables  (a) Requirements
established for flame resistant cables Trailing cables used in
coal mines shall meet the requirements established by the
Secretary for flame-resistant cables. (b) Circuit breakers;
markings and visual observation of position of disconnection
devices Short-circuit protection for trailing cables shall be
provided by an automatic circuit breaker or other no less
effective device approved by the Secretary of adequate current-
interrupting capacity in each ungrounded conductor.
Disconnecting devices used to disconnect power from trailing
cables shall be plainly marked and identified and such devices
shall be equipped or designed in such a manner that it can be
determined by visual observation that the power is disconnected.
(c) Distribution center junctions; safety connections When two
or more trailing cables junction to the same distribution
center, means shall be provided to assure against connecting a
trailing cable to the wrong size circuit breaker. (d) Tem