How many threads must be engaged if machine screws are used to fasten bonding jumpers?

When fastening bonding jumpers with machine screws, the requirement is to engage at least two threads. This is essential for ensuring a secure and reliable connection. Engaging two threads helps to provide sufficient grip and stability, minimizing the risk of loosening due to vibrations or other forces that may act on the bonded components. Adequate thread engagement is crucial in electrical applications, like bonding jumpers, to ensure continuity and safety of electrical connections. This standard contributes to the overall effectiveness and reliability of grounding and bonding systems, promoting proper electrical performance.