FAA Powerplant Written Practice Test

Which electrical wire size gauge number produces the least amount of heat with a given voltage?

1. #22 gauge wire

2. #14 gauge wire

3. #00 gauge wire

4. #10 gauge wire

The correct answer is: #00 gauge wire

The answer lies in understanding the relationship between wire gauge size, current carrying capacity, and heat generation. In electrical wiring, the larger the gauge number, the smaller the diameter of the wire. Conversely, as the gauge number decreases, the wire diameter increases. Larger diameter wires, such as #00 gauge, have a lower electrical resistance compared to smaller diameter wires. When current flows through a conductor, resistance generates heat according to Joule's law, which states that the heat produced is proportional to the square of the current multiplied by the resistance (H=I²R). Therefore, with a larger wire size having lower resistance, for a given voltage, the current draw will be reduced, leading to less heat generation. This principle means that using a #00 gauge wire minimizes the resistance in the circuit, thereby producing the least amount of heat compared to smaller gauge wires, which would generate more heat due to higher resistance for the same voltage.