14
General Information
Field Installed Control Wiring
An overall layout of the various control options available with
the required number of conductors for each control device is
illustrated in Figure 3-8.
Note: All field wiring must conform to NEC
guidelines as well as state and local codes.
Control Power Transformer
The 24 volt control power transformers are to be used only
with the accessories called out in this manual. Transformers
rated less than 50 VA are equipped with internal circuit
breakers. If a circuit breaker trips, turn “Off” all power to the
unit before attempting to reset it.
H A Z A R D O U S V O LTA G E !
DISCONNECT ALL ELECTRIC POWER INCLUDING
REMOTE DISCONNECTS BEFORE SERVICING.
Failure to disconnect power before servicing can
cause severe personal injury or death.
The transformer is located in the control panel. The circuit
breaker is located on the left side of the transformer and can
be reset by pressing in on the black reset button.
Table 3-4
AC Conductors
Distance from Unit
Recommended
to Control
Wire Size
000 - 460 feet
18 gauge
461 - 732 feet
16 gauge
733 - 1000 feet
14 gauge
Controls using DC Analog Input/Outputs
(Standard Low Voltage Multiconductor Wire)
Before installing any connecting wiring between the unit and
components utilizing a DC analog input\output signal, refer to
Figure 3-2 for the electrical access locations provided on the
unit.
a. Table 3-5 lists the conductor sizing guidelines that
must be followed when interconnecting the DC binary
output devices and the system components utilizing a
DC analog input\output signal to the unit.
Note: Resistance in excess of 2.5 ohms per
conductor can cause deviations in the accuracy of
the controls.
b. Ensure that the wiring between controls and the unit’s
termination point does not exceed two and a half (2.5)
ohms/conductor for the length of the run.
c. Do not run the electrical wires transporting DC signals
in or around conduit housing high voltage wires.
Table 3-5
DC Conductors
Distance from
Recommended
Unit to Control
Wire Size
000 - 150 feet
22 gauge
151 - 240 feet
20 gauge
241 - 385 feet
18 gauge
386 - 610 feet
16 gauge
611 - 970 feet
14 gauge
Controls using DC Communication Links
Before installing any connecting wiring between the unit and
components utilizing a DC communication link, refer to the
connection diagram that shipped with the unit for the
electrical access and connection locations provided on the
unit.
a. Wiring for the components utilizing a DC
communication link must be shielded cable (Belden
8760 or equivalent). Ground the shield at one end
only.
b. Table 3-6 lists the conductor sizing guidelines that
must be followed when interconnecting a
communication link to the unit.
c. Communication link must not exceed 5,000 feet
maximum for each link.
d. Communication link must not pass between buildings.
e. Do not run the electrical wires transporting DC signals
in or around conduit housing AC voltage wires.
Table 3-6
Maximum Communications Wiring Length
Maximum
Communication Link
Wiring Length
Maximum Capacitance
Between Conductors
1,000 feet
Up to 60 PF/FT
2,000 feet
Up to 50 PF/FT
3,000 feet
Up to 40 PF/FT
4,000 feet
Up to 30 PF/FT
5,000 feet
Up to 25 PF/FT
PF/FT = Picofarads/foot
