Program Policy Manual - VOLUME V - Mine Safety and Health ...

MSHA PROGRAM POLICY MANUAL VOLUME V
Subpart G Trailing Cables
75.600 Trailing Cables; Flame Resistance
In order to maintain the flame-resistant qualities of the cable,
this Section prohibits the use of flammable materials for
replacing the outer jacket. Only flame-resistant tapes or other
materials that have been accepted by Technical Support as the
jacketing material in permanent splice kits and jacket repair
kits will be acceptable for the repair or replacement of outer
jackets.
75.601 Short-Circuit Protection of Trailing Cables
Section 75.900 prohibits the use of fuses for the short-circuit
protection of three-phase a.c. trailing cables. Only fuses that
have been tested and approved by Technical Support under Part 28
are acceptable for the short-circuit protection of d.c. and
single-phase a.c. trailing cables. Approved fuses are identified
by an MESA or MSHA approval number. (See Sections 75.601-2 and
75.601-3.)
A length of cable meeting the requirements of Section 75.600 and
installed between a power center or rectifier and a distribution
box, and laying on the mine floor will be considered to be a
trailing cable and is required to comply with all applicable
requirements of this Subpart.
In systems where rectifiers supply ungrounded or neutral-grounded
direct-current power to mobile face equipment, short-circuit
protection must be provided for both ungrounded conductors of the
trailing cable. A properly adjusted two-pole circuit breaker or
MSHA approved fuses installed in each ungrounded conductor would
constitute compliance.
Adequate current-interrupting capacity means that the fuse or
circuit breaker is capable of safely interrupting the current
that can flow upon the occurrence of a short circuit at any point
in the protected circuit.
Enclosed circuit breakers are not acceptable as visual evidence
that the power is disconnected. Plugs and receptacles located at
the circuit breaker and trolley nips are acceptable as visual
means of disconnecting the power.
A “disconnecting device” is defined as both the trailing cable
plug (cathead) and the receptacle. Both the plug and the
receptacle must be marked in a similar manner.
June 2008 (Release V-40) 69