8
● Electrical Equipment
WARNING!
Electrical controls shall be installed and
wired by a qualified electrician. Wiring
information for the motor and controls are
furnished by the equipment manufacturer.
CONTROLS
Electrical Code: All motor controls and wiring shall con-
form to the National Electrical Code (Article 670 or other
applicable articles) as published by the National Fire
Protection Association and as approved by the American
Standards Institute, Inc.
CONTROL STATIONS
A) Control stations should be so arranged and located
that the operation of the equipment is visible from them,
and shall be clearly marked or labeled to indicate the
function controlled.
B) A conveyor which would cause injury when started
shall not be started until employees in the area are alert-
ed by a signal or by a designated person that the con-
veyor is about to start.
When a conveyor would cause injury when started
and is automatically controlled or must be controlled from
a remote location, an audible device shall be provided
which can be clearly heard at all points along the con-
veyor where personnel may be present. The warning
device shall be actuated by the controller device starting
the conveyor and shall continue for a required period of
time before the conveyor starts. A flashing light or similar
visual warning may be used in conjunction with or in
place of the audible device if more effective in particular
circumstances.
Where system function would be seriously hindered
or adversely affected by the required time delay or where
the intent of the warning may be misinterpreted (i.e., a
work area with many different conveyors and allied
devices), clear, concise, and legible warning shall be pro-
vided. The warning shall indicate that conveyors and
allied equipment may be started at any time, that danger
exists, and that personnel must keep clear. The warnings
shall be provided along the conveyor at areas not guard-
ed by position or location.
C) Remotely and automatically controlled conveyors,
and conveyors where operator stations are not manned
or are beyond voice and visual contact from drive areas,
loading areas, transfer points, and other potentially haz-
ardous locations on the conveyor path not guarded by
location, position, or guards, shall be furnished with
emergency stop buttons, pull cords, limit switches, or
similar emergency stop devices.
All such emergency stop devices shall be easily iden-
tifiable in the immediate vicinity of such locations unless
guarded by location, position, or guards. Where the
design, function, and operation of such conveyor clearly
is not hazardous to personnel, an emergency stop
device is not required.
The emergency stop device shall act directly on the
control of the conveyor concerned and shall not depend
on the stopping of any other equipment. The emergency
stop devices shall be installed so that they cannot be
overridden from other locations.
D) Inactive and unused actuators, controllers, and wiring
should be removed from control stations and panel
boards, together with obsolete diagrams, indicators, con-
trol labels, and other material which serve to confuse the
operator.
SAFETY DEVICES
A) All safety devices, including wiring of electrical safety
devices, shall be arranged to operate in a “Fail-Safe”
manner, that is, if power failure or failure of the device
itself would occur, a hazardous condition must not result.
B)
Emergency Stops and Restarts.
Conveyor controls
shall be so arranged that, in case of emergency stop,
manual reset or start at the location where the emer-
gency stop was initiated, shall be required of the con-
veyor(s) and associated equipment to resume operation.
C) Before restarting a conveyor which has been stopped
because of an emergency, an inspection of the conveyor
shall be made and the cause of the stoppage deter-
mined. The starting device shall be locked out before any
attempt is made to remove the cause of stoppage,
unless operation is necessary to determine the cause or
to safely remove the stoppage.
Refer to ANSI Z244.1-1982,American National Standard
for Personnel Protection – Lockout/Tagout of Energy
Sources – Minimum Safety Requirements and OSHA
Standard Number 29 CFR 1910.147 “The Control of
Hazardous Energy (Lockout/Tagout).”
