NEC Quiz: Article 430, Part 4

by Mark Lamendola

Quiz Questions

Code Quiz: Article 430, Part 4

Based on the 2020 NEC

Questions and answers written by Mark Lamendola, who has worked as a master electrician, electrical inspector, and design engineer. Mark is an IEEE Senior Member, and the Code article author for Codebookcity.com. Since 1996, he has been writing National Electrical Code articles for electrical trade magazines and has an extensive portfolio of hundreds of NEC articles.

Article 430 provides the requirements for motors, including the hermetic motors that also have additional requirements covered in Article 440. Many other articles also may apply to a given motor installation. Article 430 is the largest article in the NEC.

  1. The motor branch-circuit short-circuit and ground-fault protective device must be capable of carrying the X of the motor:
    A. Full Load Current (FLC).
    B. Full Load Amps (FLA).
    C. Starting current.
    D. Running current multiplied by 125%.

  2. A 150A inverse time breaker is protecting a three-phase wound-rotor motor, but the motor won't start. What are some solutions available to you?
  3. Under what conditions can you use an instantaneous trip breaker to protect a motor branch-circuit?
  4. There are three conditions that must be met if you put several motors, each 1 HP or less, on a single 120V/20A circuit. Which of the following is one of those conditions:
    A. At least one of the motors must be protected by a fuse.
    B. The branch circuit must be protected by a fuse or breaker with a rating that does not exceed that specified in 430.52 for the highest rated motor.
    C. The branch circuit must be protected by a fuse or breaker with a rating that does not exceed that specified in 430.52 for the highest rated motor plus an amount equal to the sum of the Full Load Current (FLC ) ratings of all other motors and the ratings of other loads connected to the circuit.
    D. The branch circuit must be protected by a fuse or breaker with a rating that does not exceed that specified in 430.52 for the highest rated motor plus an amount equal to the sum of the Full Load Amps (FLA ) ratings of all other motors and the ratings of other loads connected to the circuit.
  5. You need to provide short-circuit and ground-fault protection for a torque motor branch circuit. What value do you use when determining the OCPD size?

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