Abstract: An electric circuit breaker or overload protection apparatus includes a thermal element which, on being heated by a fault current, is deflected to initiate a circuit-breaking tripping of the apparatus. A supporting mechanism for varying the rating of the apparatus includes an adjusting member or slide displaceable relative to the thermal element so as to vary the action of the thermal element, a recessed manually-operable externally-accessible knob, and a rotatable boss eccentrically and adjustably mounted in the knob recess and operative upon knob rotation to cause a variance in the displacement of the adjusting member and thus a variance in the rating of the apparatus.

Abstract: An electrical circuit breaker having a thermal element which on being heated by fault current trips the breaker, and including an adjustable member to vary the action of the thermal element thereby to vary the rating of the breaker, said adjustable member comprising a slide displaceable by an eccentric boss rotatable by means of an external knob.