US Patent 7397333 Trip unit having bimetal element located outside the yoke

A trip unit in a miniature circuit breaker includes a magnetic yoke and a bimetal mounted on the outside of the yoke. The bimetal is welded at one end to a load terminal that leads to a terminal connector and at the other end to a pigtail. The pigtail, instead of the bimetal, passes through the yoke for connection to the blade of the circuit breaker. To induce a higher magnetic field for faster tripping, a second pigtail may be passed through the yoke in which one end of the second pigtail is connected to the load terminal near the terminal connector and the other end is connected to the bimetal near the load terminal connection point. The load terminal may include at least two parts, one part including the adjustment screw and the other part including the terminal screw. These parts may be separated by air or an insulator.