HOLT Electricians Practice Exam

When selecting feeder conductors, what is considered the highest rated motor?

1. Horsepower rating

2. Voltage rating

3. Full-load current rating

4. Current carrying capacity

The correct answer is: Full-load current rating

The full-load current rating is crucial when selecting feeder conductors because it represents the maximum current that a motor will draw at full load under normal operating conditions. This rating is essential for ensuring that the conductors can safely handle the electrical load without overheating or risking failure. By using the full-load current rating, electricians can size the feeder conductors appropriately to prevent voltage drop and ensure the efficiency and safety of the electrical system. While horsepower rating, voltage rating, and current carrying capacity are important considerations in the design of electrical systems, they do not provide the specific current requirements of the motor in the same way that full-load current does. Horsepower may indicate the power output of a motor but does not directly translate to current draw. Voltage rating pertains to the level of voltage the motor is designed to operate at but does not inform conductor sizing. Current carrying capacity, while relevant, is a factor in determining the conductors’ rating rather than the motor's demand itself. Therefore, relying on the full-load current rating enables electricians to select feeder conductors that will safely and efficiently support the motor's operation.