Daktronics CR-2004, Display Manual

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Electrical Installation 15
4.2 Power
Correct power installation is imperative for proper display operation. The subsections that
follow give details of display power installation.
Only qualified individuals should attempt to
complete the electrical installation; untrained personnel should not attempt to install these
displays or any of the electrical components. Improper installation could result in serious
damage to the equipment or injury to personnel.
The scoreboards in this manual require a dedicated 240 V or 120 V circuit for incoming power
(refer to the Specifications in
Section 2 ).
WARNING: It is critical that 120 V scoreboard circuits be fused at 15 A and that all
conductors used must be designed to pass a 15 A current in normal operation. For 240 V
scoreboards, consult local electrical codes. Failure to meet wiring and overcurrent
protection device requirements will void the scoreboard warranty.
Grounding
The display must be properly grounded according to local and national codes or the warranty
will be void. Proper grounding is necessary for reliable equipment operation and protects the
equipment from damaging destructive disturbances and lightning.
Daktronics recommends a resistance-to-ground of 10 ohms or less. The electrical contractor
performing the electrical installation can verify ground resistance. Daktronics Sales and
Service personnel can also provide this service.
The display system must be earth-ground. The material for an earth-ground electrode differs
from region to region and may vary according to conditions present at the site. Consult local
and national electrical codes.
Daktronics does not recommend using the support structure as an earth-ground electrode;
concrete, primer, corrosion, and other factors make the support structure a poor ground.
Note: The support structure may be used as an earth-ground electrode only if designed to do
so. A qualified inspector must approve the support structure and grounding methods.
There are two types of 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 circuit must contain an isolated earth-ground
conductor. In this circumstance, do not connect neutral to ground at the disconnect or at the
display as this would violate electrical codes and void the warranty.
Use a disconnect so that all ungrounded lines can be disconnected. The National Electrical
Code requires the use of a lockable power disconnect within sight of or at the display.