A sensor assembly includes an upper shell and a lower shell and is configured to mate together. The upper and lower shells form a cavity therebetween that extends along a length of the shells. The cavity is configured to receive a wire having an insulated jacket and a conductor. A contact member is positioned within the cavity and configured to pierce the insulated jacket and engage the conductor to establish a direct thermally conductive path to a discrete location of a main circuit. A sensor operatively connects with the contact member and is configured for detecting a temperature of the discrete location through the direct thermally conductive path.