10
BAS-SVX36C-EN
Pre-Installation
Maximum Wire Lengths
Thermostat to HVAC Equipment
The thermostat may not function properly if the total resistance of any of the thermostat to HVAC
equipment wires exceeds 2.5 ohms.To ensure that wire length does not cause excess resistance,
refer to
Table 1
and ensure that the wires from the thermostat to the HVAC equipment are not too
long.
Remote Sensor to Programmable Thermostat
Because remote temperature sensors measure resistance, very long cable runs can cause slight
errors in the measurement. For the highest temperature reading accuracy, avoid exceeding the
maximum recommended wire lengths shown in
Table 2
.
Note:
For 22 AWG (0.33 mm
2
) copper wires, the rate of error can be up to 0.5 °F (0.3 °C) per 100
,
which typically requires wire lengths in excess of 5000 ft (1500 m).
Table 1.
Maximum Thermostat to HVAC Equipment Wire Lengths
Copper wire size
Maximum recommended wire length
22 AWG (0.33 mm
2
)
150 ft (46 m)
20 AWG (0.50 mm
2
)
240 ft (73 m)
18 AWG (0.75 mm
2
)
385 ft (117 m)
Table 2.
Maximum Recommended Remote Sensor Wire Length
Copper wire size
Maximum recommended remote
sensor wire length
22 AWG (0.33 mm
2
)
1000 ft (300 m)
20 AWG (0.50 mm
2
)
1500 ft (450 m)
18 AWG (0.75 mm
2
)
2500 ft (750 m)
