Circuit breaker having dual arc chamber

A method for increasing an interrupting capacity of a circuit breaker used in an electrical circuit, comprising the steps of:

• providing first and second contact pairs which are connected in series;
• separating said first and second contact pairs when a fault is detected in said electrical circuit;
• forming first and second air gaps when said first and second contact pairs are separated to provide an effective air gap whose size is the sum of said first and second air gaps;
• and
• providing first and second arc chambers associated with said first and second contact pairs, respectively, for quenching arcs generated in said first and second air gaps when said first and second contact pairs are separated.

A circuit breaker for an electrical circuit, comprising:

• a line terminal having first and second terminal contacts;
• a contact arm having first and second arm contacts, wherein said first arm contact and said first terminal contact form a first contact pair and said second arm contact and said second terminal contact form a second contact pair and said first contact pair, said contact arm and said second contact pair are connected in a parallel arrangement;
• an operating mechanism for separating said first and second pair of contacts wherein when said first and second pair of contacts are separated first and second air gaps, respectively, are formed;
• a trip unit for actuating said operating mechanism to separate said first and second pair of contacts when a fault is detected in said electrical circuit;
• and
• first and second arc chambers associated with said first and second contact pairs, respectively, for quenching arcs generated in said first and second air gaps when said first and second contact pairs are separated.