Electrical Installation
7-2
Power Installation
There are two different 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 subsections.
Installation with Ground and Neutral Conductors Provided
For this type of installation, the power cable must contain an isolated earth-ground conductor.
In 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. (Daktronics recommends a lockable, knife-switch disconnect at the
scoreboard location so that all power lines can be completely disconnected. Use a multi-
conductor disconnect so that all hot lines and the neutral can all be disconnected. This is
important in protecting the scoreboard against lightning.)
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:
l Connect the grounding electrode cable at the local disconnect, never at the display
entrance
enclosure.
l A disconnect
that opens all
of the
ungrounded
phase
conductors
should be
used.
l The neutral
and the ground
conductors
should be
bonded in the
display power
enclosure.
Figure 3: Installation with Ground and Neutral Provided
Figure 4: Installation with Only Neutral Provided
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