Motor Disconnecting Means
The National Electrical Code, NFPA 70E and NFPA 70B all correlate. There are rules in each that address equipment disconnecting means, which are a safety requirement. Part IX of NEC Article 430 addresses disconnecting means location, types of disconnects, capacity and group installations served by a single disconnecting means. Generally, the disconnecting means must disconnect the motor(s) and motor controller(s) from the circuit.
1. “Qualified person” is defined in the NEC and NFPA 70E.
Correct Answer: True
2. If a Code rule refers to a disconnecting means “in sight from” a motor or other equipment, what is the maximum distance between the two?
Correct Answer: 50 feet
3. For an AC circuit, a general-use snap switch is not permitted to serve as the required disconnecting means for a 1.5-horsepower motor.
Correct Answer: False
4. Motor disconnecting means shall be designed so they cannot be closed automatically.
Correct Answer: True
5. A disconnecting means installed adjacent to the motor (within 3 feet) does not have to be able to being locked in the open position.
Correct Answer: True
6. At least one of the disconnecting means required by sections 430.102(A) and (B) are required to be accessible.
Correct Answer: False
7. Relative to the exception to 430.102(B), which of the following is an example of increased or additional hazards?
Correct Answer: All of the above
8. The disconnecting means for a motor shall not be permitted to be in the same enclosure as the controller.
Correct Answer: False
9. A single disconnecting means is not permitted to serve a group of motors.
Correct Answer: False
10. An inverse time circuit breaker shall be permitted as the motor disconnecting means and the controller, where operable, by which of the following means:
Correct Answer: Any of the above
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