What are the requirements for grounding a 3 phase service or a seperately derived service at the main panelboard for the following:
For a 3 wire service with no neutral I would assume there is nothing to ground in the main panel and the requirement would be that the system bonding jumper between the EGC and the transformer neutral would be done at the transformer? An EGC would be run from the transformer to the ground bus in the main panel. Is there any requirement to connect the ground bus in the main panel to an grounding electrode via a GEC
For a 4 wire service including a neutral? I would assume that you would need to connect a system bonding jumper either at the transformer or at the main panel. I would assume that you would not want to connect this at both ends, because then you would set up a parallel path for unbalanced neutral current to flow on the ground. Is a EGC required between the transformer and main panel? If system bonding jumper is installed at transformer then is there no connection between ground bus and neutral bus at main panel?
For a 3 wire service with no neutral I would assume there is nothing to ground in the main panel and the requirement would be that the system bonding jumper between the EGC and the transformer neutral would be done at the transformer? An EGC would be run from the transformer to the ground bus in the main panel. Is there any requirement to connect the ground bus in the main panel to an grounding electrode via a GEC
For a 4 wire service including a neutral? I would assume that you would need to connect a system bonding jumper either at the transformer or at the main panel. I would assume that you would not want to connect this at both ends, because then you would set up a parallel path for unbalanced neutral current to flow on the ground. Is a EGC required between the transformer and main panel? If system bonding jumper is installed at transformer then is there no connection between ground bus and neutral bus at main panel?