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Main disconnect, Main disconnect -8, 7 main disconnect – Daktronics AF-3080-68-R,A User Manual

Page 32

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Ins allation w th Only a Neutral Conductor Provided

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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

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