In metal raceway installations, feeders sharing a common neutral must be installed in which manner?

In metal raceway installations, feeders sharing a common neutral must be installed in which manner?

• A. Insulated for 600 volts
• B. Enclosed within the same raceway
• C. Shielded
• D. The same color

Answer: (B)

When two feeders share a neutral, they form a multiwire branch circuit. The neutral carries the difference between the currents in the two hot conductors, so it's important that all conductors of that circuit stay together in the same path back to the panel. Enclosing the feeders and their neutral in the same metal raceway guarantees they share the same protective enclosure and path, which helps ensure the neutral current returns through the intended route and that simultaneous disconnection of the circuit is maintained if needed. This grouping also minimizes the chance of the neutral becoming exposed to a different environment or path, which could create safety hazards. So, the appropriate installation is to keep all feeders sharing a neutral enclosed within the same raceway. The other options—insulating the conductors for a higher voltage, shielding them, or using the same color—do not address the essential arrangement needed for a shared neutral.

When two feeders share a neutral, they form a multiwire branch circuit. The neutral carries the difference between the currents in the two hot conductors, so it's important that all conductors of that circuit stay together in the same path back to the panel. Enclosing the feeders and their neutral in the same metal raceway guarantees they share the same protective enclosure and path, which helps ensure the neutral current returns through the intended route and that simultaneous disconnection of the circuit is maintained if needed. This grouping also minimizes the chance of the neutral becoming exposed to a different environment or path, which could create safety hazards.

So, the appropriate installation is to keep all feeders sharing a neutral enclosed within the same raceway. The other options—insulating the conductors for a higher voltage, shielding them, or using the same color—do not address the essential arrangement needed for a shared neutral.