How A 3-Pole Circuit Breaker Works

Understanding the single-pole breaker provides the foundation for all circuit breaker construction. The circuit breaker is designed under a spring actuated load. The circuit breaker connects power across a collapsible "bridge." When the power across the bridge, or breaker, surges to levels unsafe for the entire circuit, the bridge collapses, or the breaker trips, immediately interrupting the power flow, and opening the circuit.

In a system requiring high levels of voltage and power delivery, a multiphase system is preferable. Imagine the electricity as water flowing through a series of pipes The amount of water that can pass through a large diameter pipe can also be delivered by two or three small pipes working together. In the same way, a multiphase electrical system is designed for this purpose—to deliver higher levels of power via smaller gauge wiring, thus creating a more manageable power delivery system.

The three-pole breaker operates via the same method as a single-pole breaker. The difference is found in the amount of conductors that are connected, or bridged, by the three-pole conductor. Used most often in a three-phase electrical system, a three-pole breaker connects three different conductors, such as is often required by heavy duty industrial motors. When a surge exists anywhere in the system, across one or more of the conductors, the breaker trips, the power bridge collapses, and the circuit opens.