Johnson Controls VAV1717 - Cable and Wire Length Guidelines

Communication bus and supply power terminal blocks, ratings, and requirements
Table 7: Communication bus and supply power terminal blocks, functions, ratings, requirements, and cables
Terminal block or port label Terminal labels Function, electrical ratings and
requirements
Recommended cable type
11
+
-
FC bus communications
COM Signal reference (common) for bus
communications
FC BUS
22
SHLD Isolated terminal (optional shield drain
connection)
0.6 mm (22 AWG) stranded, 3-wire
twisted, shielded cable recommended
+
-
SA bus communications
COM SA bus signal reference and 15 VDC
common
SA BUS
2
POWER 15 VDC supply power for devices on the
SA bus
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 wires are the second
twisted pair.
TSTAT TSTAT RJ-45 8-position modular connector that
provides communications and +15 VDC
power
24 AWG 4-pair CAT 5 Cable <30.5 m
(100 ft)
SA BUS SA BUS RJ-12 6-position modular port that
provides communications and +15 VDC
power for the following devices:
• NS and NSA Series network
sensors
• MAP Gateway 4.2 or later
• Bluetooth Commissioning
Converter (BTCVT)
33
• VAV Balancing Tool
24 AWG 3-pair CAT 3 Cable <30.5 m
(100 ft)
HOT 24 VAC Power Supply - Hot
Supplies 20 VAC to 30 VAC (Nominal 24
VAC)
24~
COM 24 VAC Power Supply Common
The terminal is isolated from the FC bus
common.
0.8 mm to 1.0 mm
(20 to 18 AWG) 2-wire
1 To determine wire size and cable lengths for cables other than the recommended cables, see Cable and wire length guidelines.
2 The SA Bus and FC Bus wiring recommendations in this table are for MS/TP Bus communications at 38.4k baud. For more
information, refer to the MS/TP Communications Bus Technical Bulletin (LIT-12011034).
3 The BTCVT is supported, but no longer available for purchase. The MAP Gateway serves as a replacement for the BTCVT.
Cable and wire length guidelines
The following table defines cable length guidelines for the various wire sizes that you can use to wire low voltage (<30 V)
inputs and outputs.
VAV1717 and VAV1732 VAV Controllers Installation Guide10