CPO-PC400-W/CPO-PC400-UW HVAC CONTROLLER
EN0B-0085 IE10 R0420 14
Cable Specifications 
Power Supply Cable Specifications 
The length of the power supply cable includes the length of 
the cables to connected modules. 
NOTE: The supply voltage must, in any case, be at least 
19.2 Vac (24 Vac -20%). 
See also the connection diagrams presented in Fig. 9 
through Fig. 26 for details. 
Antenna Cable Specifications
Field Device Power Supply Cable 
Specifications 
Communication Bus Cable Specifications
Use Belden 9841 or Equivalent cable with the following 
specifications: 
RS485 Bus Cable Specifications 
• An MSTP EIA-485 network shall use shielded, twisted-
pair cable with a characteristic impedance between 100 
and 130 ohms. 
• Distributed capacitance between conductors shall be 
less than 100 pF per meter (30 pF per foot). 
• Distributed capacitance between conductors and shield 
shall be less than 200 pF per meter. 
 
 
 
Table 22. Power Supply Cable Specifications 
Device
Cable 
Length
Cable cross-
section
CPO-PC400-W/
CPO-PC400-UW
Max. 3 m  Min. 1.5 mm
2
Panel Bus I/O  Max. 3 m  Min. 1.5 mm
2
FBA  Max. 20 m  Min. 1.5 mm
2
EXPIO Max. 1200 m Min. 1.5 mm
2
CPO-DIO Max. 1200 m Min. 1.5 mm
2
C-Bus > 3 m Depends on Plug 
Gauge. See 
“Wiring 
Terminals” 
section on 
page 13
M-Bus > 3 m Depends on Plug 
Gauge. See 
“Wiring 
Terminals” 
section on 
page 13
Table 23. Antenna Cable Specifications
Device Cable Length
Cable cross-
section
Remote 
Antenna
Max. 3 m
5 mm
2
Table 24. Field Device Power Supply (24 Vac) Cable 
Specifications
Cable Length Cable Cross-section
≤ 100 m (300 ft.), single 
transformer (see 
“Example 1: Power Supply 
via Controller Using Panel 
Module” section on 
page 12.) 
min. 1.5 mm
2
 (16 AWG) 
≤ 400 m (1300 ft.), 
separate transformers 
(see “Example 2: Power 
Supply via Separate 
Transformer” section on 
page 12.) 
not allowed for > 100 m 
(300 ft) 
Table 25. Communication Cable Specifications
Interface (Buses) Cable Type
RS485 interfaces 1, 2, and 
3 (Panel Bus, BACnet Bus, 
Field Bus, Modbus, C-Bus, 
M-Bus) 
One or two pairs 
(depending on the 
application) of twisted 
pair complying with 
EIA485 standard (level IV, 
22 AWG, solid core, non-
shielded), e.g., J-Y-Y 2 x 2 x 
0.8, or shielded wire. 
RS485 interface 4 (Panel 
Bus, CP-IO Bus) 
Ethernet 1, 2 (Ethernet 
Bus) 
CPO-PC400-W/CPO-
PC400-UW can be used 
with CAT5, CAT6, and 
CAT7 cabling. Standard 
Ethernet cross-over cable, 
Cat-5, min. 10/100 
MBaud, max. length of 
100 m