Daktronics AF-3080-68-R,A - Manual (Page 32)

Ins allation w th Only a Neutral Conductor Provided t i
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 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 display
panel board.
Refer to Figure 23 below for installation details.
Figure 23: Installation with only Neutral Conductor Provided
3.7 Main Disconnect
The National Electrical Code requires the use of a lockable power disconnect near
the sign. Provide a lockable disconnect switch (knife switch) at the sign location so
that all power lines can be completely disconnected. Use a 3-conductor disconnect to
disconnect both hot lines and the neutral. Mount the main disconnect at or near the
point of power supply connection to the sign. Provide a main disconnect for each
supply circuit to the sign.
You must locate the means of disconnection in a direct line of sight from the sign or
outline lighting that it controls. This requirement provides protection by enabling a
worker to keep the disconnecting means within view while working on the sign.
Exception: You may locate the disconnecting means that are capable of being
locked in the open position elsewhere.
Electrical Installation 3-8