Maximum Wire Length by Current and
Wire Size
Figure 9: Maximum Wire Length by Current and Wire Size
Communications bus and supply power wiring guidelines
Table 7 provides information about terminal block
functions, ratings, and requirements. The table
also provides wire size, cable type, and cable length
guidelines for wiring the communication buses and
supply power.
Important:
Refer to the
N2 Modernization Guide
for Legacy N2 Controllers (LIT-12012005)
for
guidelines when you use this device on an N2
bus.
In addition to the guidelines in Table 7, observe
these guidelines when you wire the FC/SA buses
and supply power:
• Run
all
low-voltage wiring and cables separate
from high-voltage wiring.
• All FC and SA bus cables, regardless of wire size,
must be twisted, insulated, stranded copper wire.
• Shielded cable is strongly recommended for all FC
and SA bus cables.
Communications 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/Port label
Terminal labels
Function, electrical ratings/
Requirements
Recommended cable type
+
-
FC Bus Communications
COM
Signal Reference (Common) for bus
communications
FC BUS
SHLD
Isolated terminal
0.6 mm (22 AWG) stranded, 3-wire
twisted, shielded cable recommended
M4-CVM03050 VAV Controllers Installation Guide
11
