Figure 13: Maximum Wire Length by Current and Wire Size
Table 6: Communication Bus and Supply Power Terminal Blocks, Functions, Ratings, Requirements, and
Cables
Recommended Cable
Type
2
Function, Electrical
Ratings/Requirements
Terminal Labels
Terminal Block/Port Label
Use existing cable or 18 AWG
N2/FC Bus Communications
+
-
N2/FC BUS
2
Signal Reference (Common)
for bus communications
COM
Isolated terminal (optional
shield drain connection)
SHLD
0.6 mm (22 AWG) stranded,
4-wire (2 twisted-pairs),
shielded cable recommended
Note:
The + and - wires are
one twisted pair, and
the COM and SA PWR
are the second twisted
pair.
SA Bus Communications
+
-
SA BUS
SA Bus Signal Reference and
15 VDC Common
COM
15 VDC Supply Power for
Devices on the SA Bus
SA PWR
24 AWG 3-pair CAT 3 Cable
<30.5 m (100 ft)
RJ-45 8-Position Modular
Connector pr15 VDC
Power for:
•
BTCVT
3
•
VAV Balancing Tool
•
One-to-One Wireless
Receiver
TSTAT
TSTAT
20
VMA1826/1832 VAV Controller Installation Instructions
