Daktronics AF-3090-89-R,A - Manual (Page 21)

Electrical Installation
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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. 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 18 for installation details. 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
panelboard.
•
A disconnect that opens all of the ungrounded phase conductors should be used.
•
The neutral and the ground conductors should be bonded in the display panelboard.
Refer to Figure 19 for installation details.
Figure 18: Installation with Ground and Neutral Conductor Provided