RM7890A,B,C/EC7890A,B 7800 SERIES RELAY MODULES
3
66-1089—11
Wiring
WARNING
Electrical Shock Hazard.
Can cause personal injury or equipment damage.
Disconnect the power supply before beginning
installation.
1.
For proper subbase wiring and sequence chart, refer to
Fig. 2.
2.
For proper remote wiring of the KDM, refer to the
Specifications for the KDM (65-0090), Data ControlBus
Module™ (65-0091) or Extension Cable Assembly (65-
0131).
3.
Disconnect the power supply from the main disconnect
before beginning installation to prevent electrical shock
and equipment damage. More than one disconnect can
be required.
4.
All wiring must comply with all applicable electrical
codes, ordinances and regulations. Wiring, where
required, must comply with NEC, Class 1 (Line Voltage)
wiring.
5.
Use recommended wire routing of leadwires:
a. Do not run high voltage ignition transformer wires in
the same conduit with the flame detector, Data
ControlBus Module™, or Remote Reset Module
wiring.
b. Do not route flame detector, KDM, Data ControlBus
Module™, or Remote Reset Module leadwires in
conduit with line voltage circuits.
c. Enclose flame detector leadwires without armor
cable in metal cable or conduit.
d. Follow directions in flame detector, KDM, Data Con-
trolBus Module™, or Remote Reset Module Instruc-
tions.
6.
For KDM (KDM), because the KDM is powered from a
low voltage, energy limited source, it can be mounted
outside of a control panel if it is protected from
mechanical damage.
NOTE: Use 13 Vdc power supply any time more than one
KDM is used.
7.
Use maximum wire lengths:
a. RM/EC7890 leadwires: The maximum leadwire
length is 300 feet (91 meters) to terminal inputs
(Control, Running/Lockout Interlock).
b. Flame Detector leadwires: The maximum flame
sensor leadwire length is limited by the flame signal
strength.
c. Remote Reset leadwires: The maximum length of
wire is 1000 feet (305 meters) to a Remote Reset
pushbutton.
d. Data ControlBus Module™: The maximum Data
ControlBus Module™ cable length depends on the
number of system modules connected, the noise
conditions and the cable used. The maximum length
of all Data ControlBus Module™ interconnecting
wire is 4000 feet (1219 meters).
8.
For recommended wire size and type, see Table 1.
9.
The KDM, or Data ControlBus Module™ (for remote
mounting) must be wired in a daisy chain configuration,
1(a)-1(a), 2(b)-2(b), 3(c)-3(c). The order of
interconnection of all the devices listed above is not
important. Be aware that modules on the closest and
farthest end of the daisy chain configuration string
require a 120 ohm (1/4 watt minimum) resistor
termination across terminals 1 and 2 of the electrical
connectors for connections over 100 feet (31 meters).
10.
For recommended grounding practices, see Table 2.
11.
Be sure loads do not exceed the terminal ratings. Refer
to the label on the RM/EC7890 or to the terminal ratings
in Table 3.
Table 1. Recommended Wire Sizes and Part Numbers.
Application
Recommended Wire Size
Recommended Part Numbers
Line voltage terminals
14, 16, or 18 AWG copper conductor, 600
volt insulation wire.
TTW60C, THW75C, THHN90C.
Keyboard Display Module
22 AWG two-wire twisted pair with ground,
or five-wire.
Belden 8723 shielded cable or
equivalent.
Data ControlBus Module™
22 AWG two-wire twisted pair with ground,
or five-wire.
Belden 8723 shielded cable or
equivalent.
Remote Reset Module
22 AWG two-wire twisted pair, insulated for
low voltage.
—
13 Vdc full-wave rectified transformer
power input.
18 AWG wire insulated for voltages and
temperatures for given application.
TTW60C, THW75C, THHN90C.
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