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]