30 CFR § 75.1103-7
Electrical components; permissibility requirements.
The electrical components of each automatic fire sensor and warning device
system shall:
(a) Remain functional when the power circuits are deenergized as
required by §75.706; and
(b) Be provided with protection against ignition of methane or coal
dust when the electrical power is deenergized as required by
§75.313, but these components shall be permissible or
intrinsically safe if installed in a return airway.
[37 FR 16546, Aug. 16, 1972, as amended at 57 FR 20929, May 15, 1992]
EFFECTIVE DATE NOTE: At 57 FR 20929, May 15, 1992, §75.1103-7 was amended by
revising paragraph (b), effective August 16, 1992.