Mike Dolt Enterprises
Mike Dolt Enterprises
User: Average Joe, Location: New Jersey
Asked on: Monday, April 11, 2011 at 4:04 pm EDT
Answered on: Tuesday, May 14, 2024 at 4:03 am EDT
Question: Hello. A parking garage Service transformer is being removed, I am re feeding the service from a building next to it that has enough power in the Switchgear for the garage service 480V 3ph 800A. Here is my question: I'm routing two 4" EMT conduits for this I have three pull boxes in between the two services does this require Bonding bushing on the conduit? What grounding for the J-boxes and the covers? And the last is will all bonding in the parking garage Service remain the same? Will the neutral remain bonded to the grounding electrode in the parking garage?Thanks for the help..
Bonding Bushing on Conduit
Yes, bonding bushings are required on all intermediate metal conduit (IMC) or rigid metal conduit (RMC) raceways. They are installed at every point where the raceway enters or leaves a pull box or enclosure. Bonding bushings help to ensure electrical continuity and prevent the propagation of hazardous fault currents.
Grounding for J-Boxes and Covers
J-Boxes
Metal J-boxes must be grounded by connecting them to the raceway system using grounding bushings.
Covers
Metal covers for J-boxes and pull boxes must also be grounded. They can be grounded by a bonding screw that connects the cover to the J-box.
Existing Bonding in Parking Garage Service
The bonding in the existing parking garage service should remain the same. This includes: Bonding the neutral conductor to the grounding electrode system (GES) at the service panel. Bonding all exposed metal structures and enclosures to the GES. Bonding all raceways and equipment to the GES.
Neutral Bonding in Parking Garage
The neutral conductor should remain bonded to the GES in the parking garage. This is to ensure that the neutral conductor remains at or near ground potential and to prevent any voltage rise in the event of a ground fault.
Additional Notes: Ensure that all connections are tight and secure. Use proper grounding and bonding materials and methods as per applicable electrical codes and standards. Inspect and test the grounding and bonding systems regularly to ensure proper operation. Flag for review