What type of conductor must be used for bonding metal raceways?

The correct answer is the equipment grounding conductor, which is specifically required for bonding metal raceways. This type of conductor is designed to connect metal equipment, enclosures, and metal raceways to the ground, ensuring the safety of electrical installations. By using an equipment grounding conductor, any fault current is safely directed to the ground, reducing the risk of electric shock or fire hazards.

In the context of metal raceways, bonding is crucial as it helps to maintain a path for fault current and prevents the metal raceway from becoming energized, which could pose a danger to users. The NEC emphasizes the use of an equipment grounding conductor for these applications to ensure that incidental contact with the raceway does not result in electrical shock.

Other types of conductors, such as the phase conductor, neutral conductor, or grounding electrode conductor, serve different purposes in electrical systems and do not provide the specific bonding required for metal raceways. Phase conductors carry electrical current under normal operating conditions, while neutral conductors return current to the source and are not intended for grounding. Grounding electrode conductors connect the grounding system of a structure to the grounding electrodes and are not used for bonding equipment in the same way as equipment grounding conductors.