Daktronics DF-4000 - Manual (Page 16)

Mechanical and
Electrical Installation
3-2
WARNING: It is critical that the display circuit be fused at 15 A, and that all
conductors used must be designed to pass a 15 A current in normal operation.
Failure to meet wiring and over current protection device requirements is a
violation of the National Electrical Code
®
and will void the display warranty.
Refer to the DataMaster display schematics listed below and to the chart in Section 2
to determine circuit specifications and maximum power requirements for the models
described in this manual.
Grounding
Reference Drawings:
Wiring Schematic, DF-2000/4000 Series ........................... Drawing A-263988
Displays MUST be grounded according to the provisions outlined in Article 250
of the National Electrical Code and according to the specifications in this
manual. Daktronics recommends a resistance-to-ground of 10 ohms or less.
The contractor performing the electrical installation can verify ground
resistance. Technicians from Daktronics Sales and Service offices can also
provide this service.
The display system must be connected to an earth electrode installed at the display.
Proper grounding is necessary for reliable equipment operation. It also protects the
equipment from damaging electrical disturbances and lightning. The display must
be properly grounded, or the warranty will be void. Refer to the schematics,
Drawing A-263988. Connection for power wires and ground wire is made to
supplied harness pigtails inside the display. Standard NEC color code applies. (black
= hot, white = neutral, green/yellow = ground).
The material for an earth-ground electrode differs from region to region and may
vary according to conditions present at the site. Consult the National Electrical Code
and any local electrical codes that may apply. The support structure of the display
cannot be used as an earth-ground electrode. The support is generally embedded in
concrete, and if it is in earth, the steel is usually primed or it corrodes, making it a
poor ground in either case.
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 circuit 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. The