A circuit breaker which includes first and second contact pairs and a contact arm arranged in series. A first arm contact and a first terminal contact from a first line terminal form a first contact pair. A second arm contact and a second terminal contact from a second line terminal contact form a second contact pair. The first contact pair, contact arm and second contact pair are connected in a series arrangement in which the air gaps formed when the first and second contact pairs are separated combine to form an effective air gap which is double in size and thus increases an interrupting capacity of the circuit breaker. An arc chamber is associated with the first and second contact pairs for extinguishing an arc formed in the air gaps. The first and second contact pairs may also be arranged in a parallel configuration for increasing an amperage rating of the circuit breaker.