Arc Chamber/Barrier

The Arc Chamber/Barrier is an engineered enclosure within circuit breakers and fuse holders designed to confine, cool, and extinguish the plasma arc generated when interrupting fault currents. It prevents arc propagation to adjacent components, contains hot gases and metallic vapors, and facilitates rapid dielectric recovery to prevent re-ignition. This component is essential for safe interruption of short-circuit currents up to specified ratings.

When a circuit breaker opens under fault conditions, an electric arc forms between separating contacts. The arc chamber confines this arc within narrow channels or splitter plates made of arc-resistant materials. These structures stretch, split, cool, and deionize the arc plasma through several mechanisms: 1) Elongation increases arc voltage beyond system voltage, 2) Splitting divides the arc into smaller series arcs, 3) Cooling reduces thermal ionization, and 4) Gas generation from material ablation creates pressure that blows and extinguishes the arc. The barrier prevents arc flashover to grounded parts.