Journeyman Electrician Practice Exam

A size 14 AWG branch-circuit conductor protected by a 15-ampere circuit breaker supplying three 20-ampere duplex receptacles is:

1. Compliant with NEC

2. Not in compliance with NEC

3. Only compliant if devices are rated 15 amps

4. Considered safe due to overload protection

The correct answer is: Not in compliance with NEC

In this scenario, a size 14 AWG branch-circuit conductor is being used with a 15-ampere circuit breaker to supply three 20-ampere duplex receptacles. The National Electrical Code (NEC) outlines specific requirements regarding the sizing and protection of conductors in relation to the devices they supply. A size 14 AWG conductor typically has a maximum ampacity of 15 amperes. The circuit breaker, designed to protect the wiring from overloads, is also rated at 15 amperes, providing appropriate protection for the conductor. However, the key issue arises with the receptacles being rated for 20 amperes. The NEC states that branch circuits supplying receptacles must have conductors that are adequate for the load. If the receptacles are rated for 20 amps, they can facilitate heavier loads, which presents a risk when paired with conductors rated only for a maximum of 15 amps. Since the circuit breaker will only trip if the current exceeds 15 amps, and the receptacles can potentially draw more power (up to 20 amps), there lies a fundamental issue of compliance. The receptacles could be used in a configuration where they draw more than what the conductor can handle safely. Because of