Daktronics AF-3165-34-RGB - Manual (Page 20)

Electrical Installation 16
The material of an earth-ground electrode differs from region to region and from conditions present at
the site. Consult the National Electrical Code and any local electrical codes that may apply. 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.
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 in 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.
Power Installation
There are two considerations for power installation: installation with ground and neutral conductors
provided and installation with only a neutral conductor provided. These two power installations differ
slightly, as described in the following paragraphs:
Installation with Ground and Neutral Conductors Provided
For this type of installation, the power cable must contain an isolated earth-ground conductor. Under
this circumstance, do not connect neutral to ground at the disconnect or at the display. This would
violate electrical codes and void the warranty. Use a disconnect so that all hot lines and neutral can be
disconnected. Refer to Figure 17 below for installation details. The National Electrical Code requires
the use of a lockable power disconnect within sight of or at the sign.
Figure 17: Installation with Ground and Neutral Conductor Provided