124. Overheating is suspected in a high voltage bolted bus-bar joint. If the local continuity resistance is to be checked off-line after the necessary safety precautions have been taken, what instrument would be used for the resistance test?

A microhmmeter is required to accurately measure the extremely low resistance of a bolted bus-bar joint, which is essential for diagnosing overheating due to increased contact resistance. This instrument uses a high test current and a four-wire Kelvin connection to minimize measurement errors.