To avoid a voltage drop when running a thermostat wire 75 feet, which wire gauge should be used?

For running a thermostat wire over a distance of 75 feet, the choice of wire gauge is crucial to minimizing voltage drop. In this scenario, using a wire that is too thin can result in a significant voltage drop, potentially affecting the performance of the thermostat and the heating system.

The correct choice of #16 AWG wire is appropriate as it strikes a balance between sufficient thickness to minimize voltage drop while being flexible and manageable for typical thermostat installations. The acceptable voltage drop for thermostat wires is generally around 10% of the system voltage. For low voltage systems like those in many thermostats, a #16 AWG wire maintains this threshold adequately over distances such as 75 feet.

Larger gauges, such as #14 AWG or #12 AWG, while providing an even lower resistance and thus an even smaller voltage drop, may be unnecessarily thick for typical thermostat connections, making them less practical or more cumbersome to work with. In contrast, a wire gauge like #18 AWG is likely too thin, which can lead to a more significant voltage drop at 75 feet, potentially compromising the operation of the thermostat.

Thus, #16 AWG is the most effective choice for maintaining reliable performance over the specified wiring distance.