Metal raceways shall not be _____ by welding to the raceway.

The correct answer is that metal raceways shall not be terminated or connected by welding. This is aligned with the requirements of the National Electrical Code, which emphasizes safety and reliability in electrical installations. Welding can create a strong bond, but it introduces several risks, including the potential for damage to the raceway material, overheating, and structural integrity concerns.

The Code addresses these risks by prohibiting welding for the purpose of creating electrical connections or terminations. Instead, approved methods such as using mechanical connections, such as screws, or using fittings designed for secure and reliable assembly must be employed. This ensures that the raceways maintain their protective properties and that the connections remain secure over time.

In comparison, other methods mentioned like connecting by screws or supporting by brackets are acceptable practices under the Code. They follow established procedures that guarantee both electrical safety and access for maintenance. These alternatives prioritize the proper functioning of the raceway systems while mitigating risks associated with soldering or welding.