sceepe
Senior Member
Working in 40 year old building and find that it has several subpanels with only one neutral / ground bar. Thus grounded conductors and equipment grounding conductors are tied together at every sub panel. Looking a little farther, I found that none of the subpanels have a equipment grounding conductor brought to them. They are 120/208V, 3p, 4w panels feed by 3 phase conductors and neutral in pvc conduit. Thus there are no parallel return paths for objectionable current but the metallic portions of the raceway system downstream from the subpanel could have neutral current on them.
I understand that prior to 2005, it was permissible to tie the neutral to the ground in a sub panel and not run a equipment grounding conductor to the panel if it was in a separate structure. But was this allowed in 1975 for subpanels in the same building?
I understand that prior to 2005, it was permissible to tie the neutral to the ground in a sub panel and not run a equipment grounding conductor to the panel if it was in a separate structure. But was this allowed in 1975 for subpanels in the same building?
