A surgical tool can comprise an end effector, a shaft assembly, a rotatable drive shaft, a first electrical contact and a second electrical contact. The end effector comprises first and second jaw members that are pivotable relative to one another from an open position to a closed position and an electrode positioned on the first jaw member. The shaft assembly extends proximally from the end effector, is at least partially hollow, and defines an inner wall. The rotatable drive shaft extends proximally within the shaft assembly. The first electrical contact is coupled to the inner wall of the shaft assembly and positioned around at least a portion of the drive shaft. The second electrical contact is coupled to and rotatable with the drive shaft. The second electrical contact is positioned to be electrically connected to the first electrical contact as the drive shaft rotates.