A circuit interrupter (1,1') comprising: a first terminal; a second terminal; a plurality of busbars electrically connecting the first and second terminals (2, 4); separable contacts moveable between a closed position and an open position, the first and second terminals (2, 4) being electrically disconnected from each other when the separable contacts are in the open position; an operating mechanism structured to open said separable contacts; an actuator structured to cooperate with said operating mechanism to trip open said separable contacts; a printed circuit board Rogowski coil structured to sense a current flowing between the first and second terminals (2, 4); a current transformer structured to harvest power from the current flowing between the first and second terminals (2, 4); and an electronic trip unit including: an other trip function circuit structured to output a first trip signal to control the actuator to cooperate with the operating mechanism to trip open the separable contacts based on the current sensed by the printed circuit board Rogowski coil; and a thermal trip assembly structured to sense a temperature of one of the plurality of busbars and to output a second trip signal based on the sensed temperature the thermal trip assembly comprising: a fastener; an insulating sleeve; a temperature sensor structured to sense the temperature of one of the plurality of busbars; and a thermal trip circuit (30,30') structured to output the second trip signal based on the sensed temperature, wherein a portion of said insulating sleeve is disposed between the temperature sensor and said one of the plurality of busbars; and wherein the fastener couples the insulating sleeve and the temperature sensor to said one of the plurality of busbars with the insulating sleeve being in direct contact with a portion of said one of the plurality of busbars, and wherein said one of the plurality of busbars includes a flat portion (62,62') and a first connection portion that extends from a first end of the flat portion (62, 62') in a direction that is substantially perpendicular to the flat portion (62, 62'); wherein the insulating sleeve is in direct contact with the flat portion (62, 62') of said one of the plurality of busbars; and wherein said one of the plurality of busbars includes a plate portion that extends from a side of the flat portion (62, 62') in a direction that is substantially perpendicular to the flat portion (62, 62'). a first terminal; a second terminal; a plurality of busbars electrically connecting the first and second terminals (2, 4); separable contacts moveable between a closed position and an open position, the first and second terminals (2, 4) being electrically disconnected from each other when the separable contacts are in the open position; an operating mechanism structured to open said separable contacts; an actuator structured to cooperate with said operating mechanism to trip open said separable contacts; a printed circuit board Rogowski coil structured to sense a current flowing between the first and second terminals (2, 4); a current transformer structured to harvest power from the current flowing between the first and second terminals (2, 4); and an electronic trip unit including: an other trip function circuit structured to output a first trip signal to control the actuator to cooperate with the operating mechanism to trip open the separable contacts based on the current sensed by the printed circuit board Rogowski coil; and a thermal trip assembly structured to sense a temperature of one of the plurality of busbars and to output a second trip signal based on the sensed temperature the thermal trip assembly comprising: an other trip function circuit structured to output a first trip signal to control the actuator to cooperate with the operating mechanism to trip open the separable contacts based on the current sensed by the printed circuit board Rogowski coil; and a thermal trip assembly structured to sense a temperature of one of the plurality of busbars and to output a second trip signal based on the sensed temperature the thermal trip assembly comprising: a fastener; an insulating sleeve; a temperature sensor structured to sense the temperature of one of the plurality of busbars; and a thermal trip circuit (30,30') structured to output the second trip signal based on the sensed temperature, wherein a portion of said insulating sleeve is disposed between the temperature sensor and said one of the plurality of busbars; and wherein the fastener couples the insulating sleeve and the temperature sensor to said one of the plurality of busbars with the insulating sleeve being in direct contact with a portion of said one of the plurality of busbars, and wherein said one of the plurality of busbars includes a flat portion (62,62') and a first connection portion that extends from a first end of the flat portion (62, 62') in a direction that is substantially perpendicular to the flat portion (62, 62'); wherein the insulating sleeve is in direct contact with the flat portion (62, 62') of said one of the plurality of busbars; and wherein said one of the plurality of busbars includes a plate portion that extends from a side of the flat portion (62, 62') in a direction that is substantially perpendicular to the flat portion (62, 62').