30 CFR § 75.820
Electrical work; troubleshooting and testing.
(a) Electrical work on all circuits and equipment associated with
high-voltage longwalls must be performed only by persons qualified
under § 75.153 to perform electrical work on all circuits and
equipment.
(b) Prior to performing electrical work, except for troubleshooting
and testing of energized circuits and equipment as provided for in
paragraph (d) of this section, a qualified person must do the
following:
(1) Deenergize the circuit or equipment with a circuit-interrupting
device.
(2) Open the circuit disconnecting device. On high-voltage
circuits, ground the power conductors until work on the circuit is
completed.
(3) Lock out the disconnecting device with a padlock. When more
than one qualified person is performing work, each person must install
an individual padlock.
(4) Tag the disconnecting device to identify each person working
and the circuit or equipment on which work is being performed.
(c) Each padlock and tag must be removed only by the person who
installed them, except that, if that person is unavailable at the mine,
the lock and tag may be removed by a person authorized by the operator,
provided--
(1) The authorized person is qualified under paragraph (a) of this
section; and
(2) The operator ensures that the person who installed the lock and
tag is aware of the removal before that person resumes work on the
affected circuit or equipment.
(d) Troubleshooting and testing of energized circuits must be
performed only--
(1) On low- and medium-voltage circuits;
(2) When the purpose of troubleshooting and testing is to determine
voltages and currents; and
(3) By persons qualified to perform electrical work and who wear
protective gloves on circuits that exceed 40 volts in accordance with
the following table:
------------------------------------------------------------------------
Circuit voltage Type of glove required
------------------------------------------------------------------------
Greater than 120 volts (nominal) (not Rubber insulating gloves
intrinsically safe). with leather protectors.
40 volts to 120 volts (nominal) (both Either rubber insulating
intrinsically safe and non-intrinsically gloves with leather
safe). protectors or dry work
gloves.
Greater than 120 volts (nominal) Either rubber insulating
(intrinsically safe). gloves with leather
protectors or dry work
gloves.
------------------------------------------------------------------------
(4) Rubber insulating gloves must be rated at least for the nominal
voltage of the circuit when the voltage of the circuit exceeds 120
volts nominal and is not intrinsically safe.
(e) Before troubleshooting and testing a low- or medium-voltage
circuit contained in a compartment with a high-voltage circuit, the
high-voltage circuit must be deenergized, disconnected, grounded,
locked out and tagged in accordance with paragraph (b) of this section.
(f) Prior to the installation or removal of conveyor belt
structure, high-voltage cables extending from the section power center
to longwall equipment and located in the belt entries must be:
(1) Deenergized; or
(2) Guarded in accordance with § 75.816 of this part, at the
location where the belt structure is being installed or removed; or
(3) Located at least 6.5 feet above the mine floor.
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