30 CFR § 75.522-1 Incandescent and fluorescent lamps.
(a) Except for areas of a coal mine inby the last open crosscut,
incandescent lamps may be used to illuminate underground areas. When
incandescent lamps are used in a track entry or belt entry or near track
entries to illuminate special areas other than structures, the lamps shall
be installed in weather-proof sockets located in positions such that the
lamps will not come in contact with any combustible material. Lamps used in
all other places must be of substantial construction and be fitted with a
(b) Incandescent lamps within glass enclosures or fluorescent lamps
may be used inside underground structures (except magazines used for the
storage of explosives and detonators). In underground structures lighting
circuits shall consist of cables installed on insulators or insulated wires
installed in metallic conduit or metallic armor.