Abstract: A current limiting apparatus is provided with a pair of generally parallel conductive rails each including an initial high conductivity portion and a more resistive portion. A sliding armature conductor is positioned between the rails and makes sliding electrical contact with the rails such that a high fault current flowing through the rails and through the armature conductor produces forces which propel the armature conductor along the rails thereby increasing the resistance through which the current flows. Final interruption of the current is accomplished by a separate circuit breaker which is connected in series with the current limiting apparatus.