What method is used to verify tightness of accessible bolted electrical connections?

The correct answer isD. Calibrated torque wrench. In source inspection and quality surveillance of electrical equipment, the accepted method for verifying the tightness ofaccessible bolted electrical connectionsis to check them using aproperly calibrated torque wrenchagainst the manufacturer’s specified torque values. This is the most reliable way to confirm that the connection has been tightened to the required mechanical and electrical standard. Proper torque is critical because under-tightening can produce high resistance, localized heating, arcing, and eventual failure, while over-tightening can damage threads, connectors, lugs, or bus material.

The other options do not provide a true verification method.Compression of the lock-nutis not a recognized measurement of electrical connection tightness.Visual inspection of torque markingsmay indicate that tightening was performed, but it does not independently verify the actual torque achieved.Verification of an assembly check sheetonly confirms that work was recorded, not that the joint currently meets the specified torque requirement. Therefore, for source inspectors evaluating electrical assemblies, the correct and defensible method is use of acalibrated torque wrenchto verify accessible bolted electrical connections.