Arc fault circuit breaker

A circuit breaker comprising:

• a first housing defining an open first compartment;
• a second housing defining an open second compartment, and having a first opening configured therein to align with said open first compartment, said second housing assembled to said first housing to substantially enclose said first compartment;
• a first plurality of electrically connected components disposed within said first compartment, said first plurality of electrically connected components including a first interconnecting component extending into said second compartment through said first opening;
• a second plurality of electrically connected components disposed within said second compartment, said first interconnecting component providing electrical interconnection to said second plurality of components within said second compartment;
• a third housing defining an open third compartment, and having a second opening configured therein to align with said open second compartment, said third housing assembled to said second housing to substantially enclose said second compartment;
• a third plurality of electrically connected components disposed within said third compartment, said third plurality of components including a second interconnecting component providing electrical interconnection to said second plurality of components and to one component of said third plurality of components in said third compartment;
• a fourth housing defining an open fourth compartment, and having a third opening configured therein to align with said open third compartment, said fourth housing assembled to said third housing to substantially enclose said third compartment;
• a fourth plurality of electrically connected components disposed within said fourth compartment;
• and
• said second interconnecting component of said third plurality of components having one end extending into said fourth compartment through said third opening, said second interconnecting component providing electrical interconnection to said fourth plurality of components within said fourth compartment.