Electrical Wire Gauges and Load Capacities: What You Need to Know

What is the smallest copper conductor size that can carry a 21-amp load supplied by a 25-amp circuit breaker at a temperature of 130°F?

a. 10 gauge

b. 12 gauge

c. 14 gauge

Answer

The smallest THHN/THWN copper conductor that can carry a 21-amp load supplied by a 25-amp circuit breaker at a temperature of 130°F is a 12 gauge wire.

In the electrical field, it is crucial to select the correct wire gauge to ensure the safe and proper functioning of electrical circuits. When determining the appropriate wire size to carry a specific load, factors such as amperage, temperature, and circuit breaker rating must be taken into consideration.

According to the National Electric Code (NEC), in the scenario where a 21-amp load needs to be carried by a copper conductor supplied by a 25-amp circuit breaker at a temperature of 130°F, the suitable wire gauge is 12. A 12 gauge THHN/THWN wire is capable of safely carrying a 21-amp load in the specified conditions.

It is important to note that different wire gauges have varying ampacity ratings, and selecting a wire that is too small for the intended load can pose safety hazards such as overheating and potential circuit damage. By adhering to NEC guidelines and selecting the appropriate wire gauge, you can ensure the proper functioning and safety of your electrical system.