Daktronics AF-3150-20-R,A - Manual (Page 27)

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:
Electrical Installation
3-7
r Installation with Ground and Neutral Conducto s 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 20 below for installation details. The National Electrical Code
requires the use of a lockable power disconnect within sight of or at the sign.
Figure 20: Installation with Ground and Neutral Conductor Provided
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
sign panel board.
• A disconnect that opens all of the ungrounded phase conductors should be
used.
• The neutral and the ground conductors should be bonded in the sign panel
board.
Refer to Figure 21 below for installation details.