Daktronics AF-3400-64-R,A - Manual (Page 24)

Electrical Installation 3-6
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 on the back of the display.
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 because of 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.
Power Installation
There are two considerations for power installation: installation with ground and
neutral conductors provided and installation with only a neutral conductor provided.
For these displays, installation with ground and neutral conductors provided is used.
Electrical installations must be performed by qualified personnel. Unqualified
personnel should not attempt to install the electrical equipment. Serious danger to
equipment and personnel could occur if equipment is improperly installed.
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 power disconnect within sight
of or at the display.
Power Connection
Display power is connected to the power termination panel in the display. Complete
the following steps to terminate the hot, neutral, and ground wires to the termination
panel. Refer to Drawing A-192369 for assistance.
1. With a #2" screwdriver, release the four screws that hold the module in
place. The module will pull forward and out from the display.
2. Disconnect the power and signal cables from the back of the module.
3. Route the power cable through conduit to the back of the display – use one
of the ½” knockouts for access, being careful not to damage any internal
components.
4. Make the following connections as shown in Figure 16 for a single phase
display:
120/240 (Three wires plus Ground)
TB41 1 Line 1 (Hot)
2 Line 2 (Hot)
3 Neutral
E41 Ground