Situation: An industrial plant is covered under one roof, but over the years multiple sections have been added. This causes for sections of metal framing to not be interconnected.
(2) transformers have been installed. Feeders and an equipment grounding conductor installed in EMT to the primary side from the MDP, and secondary conductors out to other parts of the building. There is a bonding conductor from the transformers traveling up the wall to the ceiling cross beams. These metal beams do not connect to the building steel which is bonded to the grounding conductors.
Question: Would each grouping of interconnected metal framing need to be bonded to earth ground via a ground rod? Is it approved to use a 3/0 to bond from one metal frame to another?
If ground rods are required, would a grounding conductor be required to go from the grounding grid to each additional ground rod?
If each section is grounded separately, could that lead to different potential between systems?
(2) transformers have been installed. Feeders and an equipment grounding conductor installed in EMT to the primary side from the MDP, and secondary conductors out to other parts of the building. There is a bonding conductor from the transformers traveling up the wall to the ceiling cross beams. These metal beams do not connect to the building steel which is bonded to the grounding conductors.
Question: Would each grouping of interconnected metal framing need to be bonded to earth ground via a ground rod? Is it approved to use a 3/0 to bond from one metal frame to another?
If ground rods are required, would a grounding conductor be required to go from the grounding grid to each additional ground rod?
If each section is grounded separately, could that lead to different potential between systems?
