An arc on AC is more likely to be extinguished since the current drops to zero many times every second (so eg, on 50 Hz AC, an arc is not likely to last more th

An arc on AC is more likely to be extinguished since the current drops to zero many times every second (so eg, on 50 Hz AC, an arc is not likely to last more than 1/100 of a second). DC switches and circuit breakers are designed with greater concern for arcs.