Daktronics Galaxy AF-3400 Series, Display Manual, Page: 30 / 93

Electrical Installation
3-6
Do not connect the displays to any voltage other than that listed on the
Daktronics product label
.
Proper power installation is imperative for proper display operation. The following
sub-sections give details of display power installation.
Grounding
This sign is intended to be installed in accordance 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.
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 .
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 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 lug on the back of the display.
Power Installation
For these displays, installation with provided ground and neutral conductors is used.
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. The
National Electrical Code requires the use of a lockable disconnect within sight of or
at the display.
Figure 16 illustrates the possible main disconnects in the display.