What is the difference between a single-pole and a double-pole breaker?

What is the difference between a single-pole and a double-pole breaker?

• A. A single-pole breaker trips when two hot conductors are involved.
• B. Single-pole protects one hot conductor; double-pole provides two hot conductors and trips together for 240 V loads.
• C. Double-pole protects only one hot conductor.
• D. A double-pole breaker is used only for 120 V circuits.

Answer: (B)

The difference comes down to how many hot conductors a breaker can interrupt and how it trips. A single-pole breaker protects one hot conductor, which is typical for 120-volt circuits that run between hot and neutral. A double-pole breaker protects two hot conductors and trips them together, which is required for 240-volt loads that use both legs of the supply; because it disconnects both sides, the entire 240-volt circuit is de-energized and safer to service. In a United States split-phase system, the two hot legs are out of phase, giving 240 V between them, which is why a two-pole breaker is used for such loads. Many double-pole breakers also have a common trip or a tied handle to ensure both legs shut off simultaneously for safety and code compliance. The other statements don’t fit because a single-pole breaker doesn’t trip due to two hot conductors, a double-pole doesn’t protect only one hot conductor, and double-pole breakers aren’t limited to 120-volt circuits.

The difference comes down to how many hot conductors a breaker can interrupt and how it trips. A single-pole breaker protects one hot conductor, which is typical for 120-volt circuits that run between hot and neutral. A double-pole breaker protects two hot conductors and trips them together, which is required for 240-volt loads that use both legs of the supply; because it disconnects both sides, the entire 240-volt circuit is de-energized and safer to service. In a United States split-phase system, the two hot legs are out of phase, giving 240 V between them, which is why a two-pole breaker is used for such loads. Many double-pole breakers also have a common trip or a tied handle to ensure both legs shut off simultaneously for safety and code compliance.

The other statements don’t fit because a single-pole breaker doesn’t trip due to two hot conductors, a double-pole doesn’t protect only one hot conductor, and double-pole breakers aren’t limited to 120-volt circuits.