Abstract: An arc crowbar with electrodes separated by a gap in a protective case. Each electrode is connected to an electrically different conductor of a circuit. A sensor detects an arc flash condition on the circuit and signals a trigger circuit to send an electrical pulse to an arc-triggering device in the arc crowbar gap. The triggering device ionizes a portion of the gas between the electrodes, initiating a protective arc between the electrodes that absorbs energy from the power circuit and trips a breaker, eliminating the arc flash condition. The triggering device may be a plasma gun, especially one that injects plasma of an ablated material into the gap. The sensor may signal a circuit breaker to open in the power circuit. Arc flash sensor types may include a differential current sensor and/or an optical sensor.

Abstract: An ablative arc suppression device (10) includes a first region (16) having a first electrical arc ablation characteristic and a second region (18) having a second electrical arc ablation characteristic. The first region and the second region are configured for defining an opening (22) extending through the first region and the second region for confining an arc initiation region (24) of an electrical arc (26) to be generated within the opening. The first region and the second region are further configured for defining the opening so that the electrical arc is exposed to both the first region and the second region before exiting the opening.