Daktronics AB-1600-1.5,2.5 - Manual (Page 29)

Electrical Installation 3-7
5. Refer to the following section, Section 3.5, for important information regarding display
grounding.
Grounding
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.
Verification of ground resistance can be performed by the electrical contractor who is performing
the electrical installation. This service can also be performed by Scoreboard Sales and Service
personnel
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. Refer to Figure 36 for installation details. The National
Electrical Code requires the use of a lockable power disconnect within sight of or at the
display.