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Reference:
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Unless otherwise specified in this chapter,
make sure electrical wiring and equipment meet the requirements of
Electrical, Part L in the General safety and health standards,
chapter 296-24 WAC.
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(1) You
must make sure electrical runway conductor systems are:
(a) Designed for use in exterior
locations;
and
(b) Located so they do not come in
contact with accumulated snow or water.
(2) You must make sure cables are
protected against damage resulting from over-tensioning or other
causes.
(3) You must make
sure the control system requires the operator to follow predetermined
procedures to operate suspended or supported equipment.
(4) You must make sure the
control
system has:
(a) Devices included to
protect the equipment against electrical overloads, three-phase
reversal and phase failure;
and
(b) A separate method that is
independent of the direction control circuit to break the power
circuit in case of an emergency or malfunction.
(5) You must make sure
installations where the carriage does not have a stability factor of
at least four against overturning have electrical contacts provided
and connected so that the operating devices for suspended or
supported equipment will only function when the carriage is located
and mechanically retained at an established operating
point.
(6) You must make
sure the hoisting or suspension system has overload protection to
prevent the equipment from operating in the "up" direction with a
load greater than one hundred twenty-five percent of the rated load
of the platform.
(7) You
must make sure an automatic detector is provided for each suspension
point that will do both of the following if a suspension wire
rope
becomes slack:
(a) Interrupt power
to all hoisting motors for travel in the "down" direction;
and
(b) Apply the primary brakes.
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Note:
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A continuous-pressure rigging-bypass switch
designed for use during rigging is permitted. It can only be used
during rigging.
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(8) You must make sure upper and
lower directional switches are provided that are designed to prevent
the travel of suspended units beyond safe upward and downward levels.
(9) You must make sure
remote controlled, roof-powered manned platforms have an emergency
stop switch located adjacent to each control station on the
platform.
(10) You must
make sure cables which are in constant tension have overload devices
which will prevent the tension in the
cable from interfering with:
(a) The device that limits the
hoist from lifting a load greater than one hundred twenty-five
percent of the
rated load of the platform;
and
(b) The platform roll limiting
device required by WAC
296-870-70050,
Suspended working platforms and manned platforms used on
supported
equipment.
