A circuit interrupter includes an arc extinction assembly for magnetically driving or blowing out an arc formed between a stationary contact and a movable contact. The assembly comprises a pair of coaxial windings which are disposed in proximity to the contacts so that the internal lines of magnetic force generated by and passing inside of the windings can act directly on the arc for magnetically driving the arc in one direction. A magnetic flux diverting yoke is provided in association with the windings to diverse therethrough the external lines of magnetic force generated by and passing outside of the windings such that the arc and a portion of the movable contact arm carrying the same will not be under the influence of the external lines of magnetic force even when the contact separation proceeds to a stage where the arc is extended past the region which is totally under the influence of the internal lines of magnetic force. Otherwise, the external lines of magnetic force would pass through the arc and the portion of the movable contact arm in the opposite direction to the internal lines of magnetic force, causing the adverse magnetic effect of retarding the arc extinction and contact separation.
