CEI Motor & Motor Control Inspection Flashcards

According to NEC Article 430, what is the minimum branch-circuit conductor ampacity for a single motor?

Answer: 125% of the motor full-load current

NEC 430.22 requires motor branch-circuit conductors to have an ampacity of not less than 125% of the motor's full-load current rating.

What device is required by NEC Article 430 to protect a motor from overheating under running conditions?

Answer: Overload protection device

NEC 430.31 requires overload protection to protect motors, motor-control apparatus, and motor branch-circuit conductors from excessive heating due to motor overloads and failure to start.

Which NEC article governs the installation of motors and motor controllers?

Answer: Article 430

NEC Article 430 covers motors, motor branch circuits, and motor controllers, including their installation requirements.

When inspecting a motor disconnecting means, what is the minimum horsepower rating requirement for motors rated over 2 hp at 600V or less?

Answer: The disconnect must be rated at least equal to the motor's hp

Per NEC 430.110, the disconnecting means for a motor must have a horsepower rating not less than the motor's rated horsepower.

What is the maximum distance allowed between a motor disconnect and the motor controller, according to NEC 430.102?

Answer: Within sight from the controller

NEC 430.102(A) requires the disconnecting means to be in sight from the controller location, meaning visible and not more than 50 feet away.

During an inspection of a motor installation, you find the overload relay set at 140% of the motor's full-load current. This is most likely acceptable for which type of motor?

Answer: A motor with a service factor of 1.15 or greater

NEC 430.52 allows overload devices to be set up to 140% of full-load current for motors with a marked service factor of 1.15 or greater.