Daktronics Galaxy AF-3200 Series, Manual

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Grounding
This sign is intended to be installed with the requirements of Article 600 of the
National Electrical Code and/or other applicable local codes. This includes
proper grounding and bonding of the sign.
Displays must be grounded according to the provisions outlined in Article 250 of the
National Electrical Code
®
. Daktronics requires a resistance to ground of 10 ohms or
less. Verification of ground resistance can be performed by the electrical contractor
who is performing the electrical installation. Daktronics Sales and Service personnel
can also perform this service
The display system
must be connected to earth-ground. Proper grounding is
necessary for reliable equipment operation. It also protects the equipment from
damaging electrical disturbances and lightning.
The display must be properly
grounded or the warranty will be void.
Figure 16: Display Grounding
A minimum of one grounding electrode must be installed for each display face. The
grounding electrode is typically one grounding rod for each display face. Other
grounding electrodes as described in Article 250 of the National Electric Code may
be used. Daktronics requires that the resistance to ground be 10 ohms or less. If the
resistance to ground is higher than 10 ohms, it will be necessary to install additional
grounding electrodes to reduce the resistance. The grounding electrode should be
installed within 25 feet of the base of the display. The grounding electrode must be
connected to the ground terminal in the display panel board.
This grounding electrode must be installed in addition to the equipment-grounding
conductor that should be part of the power installation. The material of an earth-
ground electrode differs from region to region and from conditions present at the
site. The support structure of the display cannot be used as an earth ground electrode.
The support is generally embedded in concrete, and if in earth, the steel is either
primed or it corrodes, making it a poor ground.
Electrical Installation
3-5