Branch circuit load rating applies to which parts of the electrical system?

• A. Branch circuits
• B. Service feeders
• C. Both A and B
• D. Neither A nor B

Answer: (A)

The concept here is that the term “load rating” is applied to branch circuits—the portions of the electrical system that run from a branch-circuit overcurrent device in the panel to outlets, lighting, and other loads. A branch circuit is protected and sized for a specific ampacity (for example, a 15-amp or 20-amp circuit), based on the conductors and protection used. Service feeders, by contrast, carry power from the service equipment to the distribution panels and are sized and rated differently; their purpose and calculation aren’t described by a branch-circuit load rating. So, the load rating concept specifically applies to branch circuits.