Ats And Accessory Communication Connections; Communication Cable Specifications - Kohler 14RCAL Installation Manual

3.3

ATS and Accessory Communication Connections

The following sections cover communication connections from the generator set to automatic transfer switches and RBUS
accessories, including the programmable interface module (PIM) and the load shed kit.
3.3.1

Communication Cable Specifications

RBUS Connections A and B
For the RBUS communication connections A and B to the optional RBUS modules, use 20 AWG shielded, twisted -pair
communication cable. Belden #9402 (two-pair) or Belden #8762 (single-pair) or equivalent cable is recommended. Optional
RBUS modules can include the Model RXT transfer switch, RXT combined interface/ load management board, automatic
paralleling module (APM), programmable interface module (PIM), and/or the load shed kit for the RDT or RXT transfer swit ch.
For outdoor installations, including those with buried cables and/or conduit, use outdoor-rated Belden #1075A or equivalent
20 AWG shielded, twisted-pair communication cable.
PWR and COM Connections
For the PWR and COM connections, the cable size and maximum cable length depends on the number of modules connected.
See Figure 27.
•
For short cable runs shown in the first two rows of Figure 27, use one pair in the two-pair communication cable for the
A and B connections, and use the second pair for the PWR and COM connections.
•
For the longer cable runs shown in the last two rows of Figure 27, use 12 or 14 AWG cable for PWR and COM, and
use the 20 AWG communication cable specified above for the A and B connections only. In this case, single-pair
communication cable such as Belden #8762 can be used for the A and B connections.
Cable (TB1- PWR and COM)
Belden #9402 or equivalent 20AWG for indoor
installations
Belden #1075A or equivalent 20AWG for outdoor
installations or buried cables
14 AWG *
12 AWG *
 Use 12 or 14 AWG cable for PWR and COM connections only. For RBUS connections A and B, use shielded, twisted pair
communication cable specified above.
Figure 27 Total Cable Lengths for PWR and COM Connections
TP-7091 11/22
Maximum length per run, meters (ft.)
Number of Modules (RXT, APM, PIM, and/or load management device) per Run
1 Module 2 Modules
46 (150) 15 (50)
46 (150) 15 (50)
137 (450) 137 (450)
137 (450) 137 (450)
3 Modules 4 Modules
Do not use 20AWG
5 (17)
for PWR and COM
Do not use 20AWG
5 (17)
for PWR and COM
107 (350) 107 (350)
137 (450) 137 (450)
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