Gas Heat ESCO Practice Exam

To control voltage drop over a long wire run to a thermostat, a technician should use what gauge wire for a 75-foot run?

1. 12 AWG

2. 16 AWG

3. 18 AWG

4. 20 AWG

The correct answer is: 18 AWG

A 12 AWG wire is too thick and costly for this length of run. The thicker the wire, the lower the gauge number, and the more expensive it is. A 16 AWG wire is also too thick for a 75-foot run and may not be as cost-effective. It could also potentially cause excessive voltage drop if the thermostat does not require that much power. A 20 AWG wire is too thin for this length of run. The thinner the wire, the higher the gauge number, and the more likely it is to experience voltage drop. Overall, using an 18 AWG wire is the most appropriate and economical choice for controlling voltage drop in a 75-foot wire run to a thermostat. Its gauge falls in the middle range, which will provide enough power while also being cost-effective.