CEI CEI Motor & Motor Control Inspection 1

Question 1

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

Accepted Answer

125% of the motor full-load current

Answer

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.

Question 2

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

Accepted Answer

Overload protection device

Answer

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.

Question 3

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

Accepted Answer

Article 430

Answer

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

Question 4

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

Accepted Answer

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

Answer

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

Question 5

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

Accepted Answer

Within sight from the controller

Answer

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.

(CEI) Certified Electrical Inspector Practice Test

(CEI) Certified Electrical Inspector Practice Test

CEI CEI Motor & Motor Control Inspection 1