How must all metal raceways, fittings, and enclosures be connected according to NEC®?

The requirement for connecting all metal raceways, fittings, and enclosures according to the National Electrical Code (NEC) is that they must be metallically joined. This means that the connections should provide a continuous electrical path to ensure proper grounding and bonding, minimizing the risk of electrical faults and enhancing the safety and reliability of the electrical system.

Metal raceways, fittings, and enclosures are designed to contain and protect electrical conductors and must maintain integrity in terms of both physical structure and electrical connectivity. Metallic connections ensure that there is a low-resistance pathway for fault currents, which is crucial for protective devices to operate correctly in the event of a short circuit or ground fault.

This requirement emphasizes the importance of ensuring that connections between components are reliable and conductive, which may involve using mechanical means, such as screws, clamps, or other types of metallic joining methods, to maintain electrical continuity. Other options like welded or bolted connections do not inherently provide the full assurance of an electrically continuous path as directly supported by the NEC’s emphasis on metallic joining.