(a) A power-shutoff component shall be suitably constructed for
incorporation in or with permissible and approved equipment that is operated
in gassy mines and tunnels.
(b) The power-shutoff component shall include:
(1) A means which shall be made to function automatically
to deenergize the machine or equipment when actuated by the methane detector
at a methane concentration of 2.0 volume percent and at all higher
concentrations in the mine atmosphere.
(b)(1)(i) For an electric-powered machine or equipment
energized by means of a trailing cable, the power-shutoff component shall,
when actuated by the methane detector, cause a control circuit to shut down
the machine or equipment on which it is installed; or it shall cause a
control circuit to deenergize both the machine or equipment and the trailing
Note: It is not necessary that power be controlled both at the machine and at
the outby end of the trailing cable.
(b)(1)(ii) For a battery-powered machine or equipment, the
methane-monitor power-shutoff component shall, when actuated by the methane
detector, cause a control circuit to deenergize the machine or equipment as
near as possible to the battery terminals.
(b)(1)(iii) For a diesel-powered machine or equipment, the
power-shutoff component, when actuated by the methane detector, shall shut
down the prime mover and deenergize all electrical components of the machine
or equipment. Batteries are to be disconnected as near as possible to the
battery terminals. Headlights which are approved under Part 20 of this
subchapter (Schedule 10, or any revision thereof) are specifically exempted
from this requirement.
(2) An arrangement for testing the power-shutoff
characteristic to determine whether the power-shutoff component is
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