Daktronics Galaxy AF-3050 Series, Display Manual

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3.5 Power
Proper power installation is imperative for proper display operation. The following sub-sections give
details of display power installation.
Qualified personnel must perform electrical installations.
Unqualified personnel should not attempt to install the electrical equipment. Serious danger to
equipment and personnel could occur if equipment is improperly installed.
G ounding r
Displays must be grounded according to the provisions outlined in Article 250 of the National
Electrical Code
®
. Daktronics recommends a resistance to ground of 10 ohms or less. The electrical
contractor who is performing the electrical installation can perform verification of ground
resistance. 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.
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.
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. The National Electrical Code requires the use of a
lockable power disconnect within sight of or at the display.
Installation with Only a Neutral Conductor Provided
Installations where no grounding conductor is provided must comply with Article 250-32 of
the National Electrical Code. If the installation in question meets all of the requirements of
Article 250-32, the following guidelines must be observed:
·
Connect the grounding electrode cable at the local disconnect, never at the display driver
enclosure.
·
A disconnect that opens all of the ungrounded phase conductors should be used.
·
The neutral and the ground conductors should be bonded at the ground lug termination
point in the receptacle within the display driver enclosure.
Electrical Installation
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