Daktronics FB-2006 Generation III Stackable LED Scoreboard - Manual (Page 26)

20 Electrical Installation
The display system must be connected to an earth electrode installed at the display.
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. Refer to the schematic, Drawing
A-177931, for information on where to connect the grounding wire. The connection
is illustrated in the "Pwr In" detail of the Master Configuration portion of the
schematic.
The material for an earth-ground electrode differs from region to region and may
vary according to 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 it is in earth, the steel is usually primed or it corrodes,
making it a poor ground in either case.
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 circuit 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/power enclosure.

Use a disconnect that opens all of the ungrounded phase conductors.