Daktronics DF-1050/1051/1052/1053 - Manual (Page 21)

Electrical Installation 3-3
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 neutrals can be disconnected. The
National Electrical Code requires the use of a lockable power disconnect within sight
of or at the display.
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
display driver/power enclosure.
• Use a disconnect that opens all of the ungrounded phase conductors.
3.3 Lightning Protection
The use of a disconnect near the display to completely cut all current-carrying lines
significantly protects the circuits against lightning damage. The National Electrical
Code also requires it. In order for this device to provide protection, the power must
be disconnected when the display is not in use. The control console should also be
disconnected from power and from the signal j-box when the system is not being
used. The same surges that may damage the display's driver can also damage the
driver console's circuit.
3.4 Signal Connection
Reference Drawing:
Enclosure Driver, 4 Col MASC, Wide .......................... Drawing A-191943
Electrical Specification Drawings ............................. Refer to Appendix A
To gain access to the driver enclosure, open the access door and remove the cover
from the enclosure. Refer to the Electrical Specification Drawings for the access
location for your sign.
Route power and signal cables into either side of the display, where there is a
separate knockout for signal conduit. The signal cable terminates to the signal
terminal block (TB3) in the driver enclosure, immediately below the power supply
and to the right of the power connectors. The component is a dual-row barrier
terminal block, and it accommodates “Signal In,” “Signal Out,” and “12 V DC Out”
as well as “Inc” (increment), “Dec” (decrement), “Open,” “Full” and “Common”
terminals for operating the display from switches.