Code Quiz
Jun 13, 2007 7:43 PM, By Steven Owen
Q. When installing a high-impedance grounded neutral system for a 480V, 3-phase electrical system, the following question arises. Where is the proper location for the grounding impedance (resistor)?
- Between the equipment bonding jumper and the system neutral.
- Between the main bonding jumper and the system neutral.
- Between the transformer secondary and the first disconnecting means.
- Between the grounding electrode conductor and the system neutral.
Answer: D
As per 250.36(A), “The grounding impedance shall be installed between the grounding electrode conductor and the system neutral. Where a neutral is not available, the grounding impedance shall be installed between the grounding electrode conductor and the neutral derived from a grounding transformer.”
Owen is the owner and president of National Code Seminars and the holder of master electrician certifications in 46 states. He can be reached at necexpert@aol.com.
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