High-impedance grounded neutral systems shall be permitted under which circumstances for 3-phase AC systems of 480 volts to 1,000 volts?

Prepare for the NEC Apprentice of the Year Test with detailed multiple choice questions and comprehensive explanations. Build knowledge and confidence to excel in your exam!

High-impedance grounded neutral systems are a specific type of grounding configuration used in electrical systems to improve safety and reliability. The allowance of high-impedance grounded neutral systems for 3-phase AC systems between 480 volts and 1,000 volts is contingent upon multiple factors that enhance the effectiveness and safety of the system.

The correct answer encompasses all provided circumstances.

When qualified persons service the installation, it ensures that only individuals with appropriate training and knowledge are involved in the work, enhancing safety and proper system handling.

The installation of ground detectors on the system is crucial because these devices monitor ground fault conditions. They alert personnel to any fault situations, which is essential in high-impedance grounded systems where fault currents are intentionally reduced. This allows for prompt response to potentially hazardous situations without compromising system operation.

Excluding line-to-neutral loads from the system is also vital, as these loads can introduce additional complications in fault situations. By ensuring that the system does not supply line-to-neutral loads, the risks associated with unbalanced loads and unintended ground faults are minimized, maintaining system integrity.

Therefore, all of these conditions are collectively necessary to promote safe and effective operation of high-impedance grounded neutral systems in the specified voltage range.

Subscribe

Get the latest from Examzify

You can unsubscribe at any time. Read our privacy policy