Johnson Controls System 450 Series Technical Bulletin page 23

Table 7: System 450 wiring terminals and wire sizes
Terminal block type Terminal label
Line-voltage output LNC1, LNC2
relay terminal blocks
Control and expansion
modules with relay
output
LNO1, LNO2
LC1, LC2
Line-voltage supply 240 VAC
power terminal block
No label on the
Power modules only
middle terminal
120 VAC
Figure 6 shows the location of and designations for the wiring terminals on a C450YNN power
module. provides descriptions, ratings, requirements, and recommended wire sizes for a C450YNN
power module.
Figure 6: C450YNN power module
Table 8: C450YNN power module
Callout Description
1 High-voltage supply power terminals
System 450 Series C450CCU Condensing Unit Control System Technical Bulletin
Terminal function
Connects equipment control circuit to the
line-voltage normally closed (LNC) contact
on the SPDT relay.
LNC2 terminals are only on control and
expansion modules with two output relays.
Connects equipment control circuit to the
line-voltage normally open (LNO) contact on
the SPDT relay.
LNO2 terminals are only on control and
expansion modules with two output relays.
Connect line power to the line-voltage
common (LC) on the SPDT relay so that
the control module can switch line voltage
to the LNC or LNO terminals to energize
connected equipment control circuits.
LC2 terminals are only on control and
expansion modules with two output relays.
Left terminal is for one 240 VAC supply
power lead.
Middle terminal is the common connection
for either the 120 VAC or 240 VAC supply
power lead.
Right terminal is for one 120 VAC supply
power lead.
Wire sizes
2 2
0.08 mm to 2.50 mm
28 AWG to 14 AWG
2 2
0.34 mm to 2.50 mm
22 AWG to 14 AWG
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