Cable And Wire Length Guidelines; Maximum Cable Length Versus Load Current - Johnson Controls Metasys MS-IOM4711 Series Installation Instructions Manual

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.
Table 4: Cable Length Guidelines for Recommended Wire Sizes for Low-Voltage (<30 V) Inputs and Outputs
Guideline Wire Size/Gauge and Type
A 1.0 mm (18 AWG) stranded copper
0.8 mm (20 AWG) stranded copper
0.6 mm (22 AWG) stranded copper
0.5 mm (24 AWG) stranded copper
B 1.0 mm (18 AWG) stranded copper
0.8 mm (20 AWG) stranded copper
0.6 mm (22 AWG) stranded copper
0.5 mm (24 AWG) stranded copper
C See Figure 8
Use stranded copper wire.

Maximum Cable Length versus Load Current

Use Figure 8 to estimate the maximum cable length relative to the wire size and the load current (in mA) when wiring
inputs and outputs.
Note: Figure 8 applies to low-voltage (<30 V) inputs and outputs only.
Figure 8: Maximum Wire Length for Low-Voltage (<30V) Inputs and Outputs by Current and Wire Size
IOM47 Input/Output Module Installation Instructions
to select wire size/gauge.
Maximum Cable
Length and Type
457 m (1,500 ft) twisted
wire
297 m (975 ft) twisted wire
183 m (600 ft) twisted wire
107 m (350 ft) twisted wire
229 m (750 ft) twisted wire
137 m (450 ft) twisted wire
91 m (300 ft) twisted wire
61 m (200 ft) twisted wire
See Figure 8 to determine
cable length. Use twisted
wire cable.
Assumptions
100 mV maximum voltage drop
Depending on cable and the connected input
or output device, you may have to define an
offset in the setup software for the input or
output point.
100 mV maximum voltage drop
Depending on cable and the connected input
or output device, you may have to define an
offset in the setup software for the input or
output point.
N/A
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