Arc Runners/Splitter Plates

Arc runners and splitter plates are critical safety components within arc quenching chambers of electrical switchgear and circuit breakers. These metallic plates are strategically arranged to split high-current electrical arcs into multiple smaller arcs, increasing surface area for cooling and deionization. They work by creating a series of arc roots that move along the plates, stretching and cooling the plasma until the arc voltage exceeds the system voltage, causing extinction. The plates are typically made of arc-resistant materials with high thermal conductivity and are designed with specific geometries to optimize arc movement and cooling efficiency.

When an electrical fault creates an arc, the arc is drawn onto the plates by electromagnetic forces and thermal gradients. The splitter plates divide the main arc into multiple series arcs, increasing total arc voltage. As the arcs move along the plates, they are cooled through radiation, convection, and conduction. The increased arc voltage and cooling reduce current density and plasma temperature until the arc can no longer sustain itself and extinguishes.