Mike Dolt Enterprises
Mike Dolt Enterprises
User: Gategator37, Location: Tennessee
Asked on: Wednesday, April 6, 2011 at 1:36 pm EDT
Answered on: Tuesday, May 14, 2024 at 3:51 am EDT
Question: The electrician used a Main Bonding Jumper from the Neutral Conductor to the Grounding Electrode System located in the 112.5 Transformer. This is all fine and dandy; however, at the neutral bar (at transformer) he also landed his EGC's from the primary and secondary panelboards. Is this installation ok, or should he of attached the EGS's to the Ground Bar located at the Transformer. I don't know if the only thing that can attach to the neutral is the "bonding Jumper".Thanks in advance for your input.
Incorrect Installation
The electrician's installation is incorrect. EGCs (Equipment Grounding Conductors) should
never be connected to the neutral bar. The neutral conductor is a current-carrying conductor, while the EGC is a safety conductor that should be connected to the grounding electrode system (GES).
Proper Installation
The Main Bonding Jumper should be connected from the neutral conductor to the GES, as the electrician has done. The EGCs from the primary and secondary panelboards should be connected to the
ground bar located at the transformer.
Reasoning
The neutral conductor carries current back to the electrical source. If an EGC is connected to the neutral bar, fault current could flow back through the neutral conductor and defeat the purpose of the EGC. The ground bar provides a direct path for fault currents to flow back to the GES, ensuring that electrical faults are safely discharged.
National Electrical Code (NEC) Requirement
NEC 250.24(A)(5) states: "Equipment grounding conductors shall not be connected to the neutral conductor on the supply side of the service disconnecting means or on the supply side of the main disconnecting means for separately derived systems."
Conclusion:
The electrician must correct the installation by moving the EGCs from the neutral bar to the ground bar located at the transformer. This will ensure proper grounding and electrical safety. Flag for review