Which of the following is a permitted method of ensuring continuity when bonding metallic service raceways to metal service equipment?

• A. Listed bonding type lock nuts
• B. Duct tape
• C. Soldered joints only
• D. Rivets

Answer: (A)

Maintaining a continuous electrical bond between metal raceways and the service equipment is essential to provide a reliable path for fault current. The proper way to ensure this continuity is to use hardware that is specifically listed for bonding; listed bonding type lock nuts are designed to create and maintain that conductive connection as the conduit is secured to the service equipment, meeting the bonding requirements.

Duct tape is not an approved bonding method—its adhesive and material can degrade, and it does not provide a reliable, code-approved electrical connection. Soldered joints alone aren’t typically relied upon for this purpose in service installations because they can crack or fail under vibration and thermal cycling, and many code provisions require mechanically secure, listed bonding connections. Rivets don’t guarantee an electrical bond unless they are specially listed for bonding purposes, which standard rivets generally are not.