Electrician's Licensing Practice Exam

How many amps can a 10 AWG wire carry, and what is the appropriate breaker size?

1. 20 amps with a 15 amp breaker

2. 30 amps with a 20 amp breaker

3. 40 amps with a 30 amp breaker

4. 50 amps with a 40 amp breaker

The correct answer is: 30 amps with a 20 amp breaker

A 10 AWG wire is generally rated to carry a maximum of 30 amps for most applications under typical conditions. However, it is essential to pair this wire with an appropriately sized breaker to ensure safety and compliance. The correct breaker size for a 10 AWG wire is 30 amps. Using a 20 amp breaker with a 10 AWG wire is not appropriate because the wire can handle more current than the breaker would allow, leading to potential overloading without tripping. Similarly, opting for a higher-rated breaker, such as a 40 amp or 50 amp breaker, would put the wiring at risk of overheating since the wire is not designed to safely handle currents above its rated capacity. Therefore, the choice of a 30 amp breaker aligns perfectly with the carrying capacity of the 10 AWG wire, thus ensuring both functionality and safety. This understanding is crucial for electricians, as it is vital to select the right wire gauge and breaker size to prevent electrical hazards, including fires.