Johnson Controls M4-XPM Installation Manual page 9

Cable and wire length guidelines
Table 4 defines cable length guidelines for the various wire sizes that may be used for wiring low-voltage (<30 V) input
and outputs. The required wire sizes and lengths for high-voltage (>30 V) Relay Outputs are determined by the load
connected to the relay, and local, national or regional electrical codes.
Table 4: Cable length guidelines
Guideline Wire size/Gauge and type
A 1.0 mm (18 AWG) stranded copper
0.8 mm (20 AWG) stranded copper 297 m (975
ft) twisted wire
0.6 mm (22 AWG) stranded copper 183 m (600
ft) twisted wire
0.5mm (24 AWG) stranded copper 107 m (350 ft)
twisted wire
B 1.0 mm (18 AWG) stranded copper
0.8 mm (20 AWG) stranded copper 297 m (975
ft) twisted wire
0.6 mm (22 AWG) stranded copper 183 m (600
ft) twisted wire
0.5 mm (24 AWG) stranded copper 107 m (350
ft) twisted wire
C
See Figure 10 to select wire size/gauge.
Use stranded copper wire.
Maximum cable length versus load current
Use the following figure to estimate the maximum cable
length relative to the wire size and the load current (in
mA) when wiring inputs and outputs.
Figure 10: Maximum wire length for low-voltage (<30 V) Inputs and Outputs by current and wire size
Maximum cable length Assumptions
and type
457 m (1,500 ft) twisted 100 mV maximum voltage drop
wire
Depending on the cable length and the
connected input or output device, you may
297 m (975 ft) twisted
have to define an offset in the setup software
wire
for the input or output point.
183 m (600 ft) twisted
wire
107 m (350 ft) twisted
wire
229 m (750 ft) twisted 100 mV maximum voltage drop
wire
Depending on the cable length and the
connected input or output device, you may
137 m (450 ft) twisted
have to define an offset in the setup software
wire
for the input or output point.
91 m (300 ft) twisted wire
61 m (200 ft) twisted wire
See Figure 10 to N/A
determine cable length.
Use twisted wire cable.
Note: Figure 10 applies to low-voltage (<30 V) inputs
and outputs only.
M4-XPM Expansion Modules Installation Guide 9