Gas Heat ESCO Practice Exam

What are the two standard gauges for thermostat wire?

1. 14 and 16 AWG

2. 16 and 18 AWG

3. 12 and 14 AWG

4. 18 and 20 AWG

The correct answer is: 18 and 20 AWG

The two standard gauges for thermostat wire are typically 16 and 18 AWG. These gauges are commonly used because they strike a balance between the wire's capacity to carry the low voltage signals required for thermostats and their flexibility for easy installation. The 18 AWG wire is often used for low-power applications, while 16 AWG can handle slightly higher loads, making them suitable for the various components in heating and cooling systems. Using heavier gauge wire, such as 12 or 14 AWG, would be unnecessary and potentially cumbersome for the low-voltage thermostat applications. On the other hand, 20 AWG wire is generally too thin for reliable performance in these situations, as it may not effectively carry the signals without significant voltage drop or risk of overheating. Therefore, the correct choice reflects the industry standards for thermostat wire in HVAC applications.