Installation Guide

TP-7091 2/21 31Section 3 Electrical
3.3.3 System Connections with
Accessory Modules
See Figure 3-9 through Figure 3-13 for connection
options to RBUS accessory modules. Note the cable
shield connections shown in Figure 3-9.
Note: Refer to the installation instructions provided with
the automatic paralleling module (APM) for
RBUS connections to the APM.
The maximum cable length depends on the number of
RBUS modules connected. See Figure 3-6 for the
maximum cable lengths with 1, to 4 modules per cable
run.
Note: A model RXT transfer switch with combined
interface/ load management board acts as two
RBUS modules: one RXT transfer switch and
one load management device.
Power Relay Modules are not RBUS modules and do
not add to the number of modules in Figure 3-6.
Generator Set
GND
A
B
COM
PWR
RBUS
12VDC
RXT*
COM
COM
PWR
COM
PWR
PWR
B
A
B
A
B
A
COM
PWR
B
A
COM
PWR
B
A
4
5
2
1
3
5
Load Shed Kit
PIM
COM
PWR
B
A
1. Generator set terminal block. See Figure 3-3 for
location. Check the decal on the generator set for
terminal block connections.
2. Connect one end of each cable shield to GROUND at
the generator set.
3. Communication cable. See Figure 3-6 for cable
specifications, including maximum total cable length.
4. Connect shields together as shown.
5. Leave one end of each cable shield disconnected at the
last device.
Note: Connect A to A, B to B, PWR to PWR, and COM
to COM.
See Section 3.3.1, Cable Specifications.
* RXT transfer switch with standard or combined
interface/load management board. Do not use a load
shed kit with a combined interface board.
4
3
Figure 3-9 Accessory Module Communication Connection Details