Which of the following categories is NOT included in types of circuit breakers?

The correct category of circuit breakers that is not included in typical classifications is DC breakers. Most standard circuit breaker classifications focus on alternating current (AC) applications, which include a variety of breakers designed for specific safety and operational requirements.

240-volt pole breakers, GFCI (Ground Fault Circuit Interrupter) breakers, and AFCI (Arc Fault Circuit Interrupter) breakers are all well-established types of circuit breakers designed primarily for AC circuits.

240-volt pole breakers are commonly used in residential and commercial applications to protect circuits that require a higher voltage. GFCI breakers provide ground fault protection, which is crucial for preventing electrical shock in wet areas. AFCI breakers help prevent fires by detecting arc faults, which may result from damaged wires.

In contrast, while DC breakers do exist, they are not typically categorized with the more familiar AC breakers in residential and commercial installations, making them less relevant in this context. Thus, DC breakers are rightly identified as the category that is not included with the others listed.