Daktronics Galaxy AF-3080 Series, Display Manual

Page: 30 / 107

Figure 21: 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 recommends 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. The grounding system and grounding
electrodes must be installed according to Article 250 of the National Electrical Code
and any applicable local codes.
Electrical Installation
3-6