Hi everyone,
This forum is great and I have been looking at it for years, until today (I just joined, thank you for the great forum) to get some help with the following situation:
I have a sub-panel in a detached garage with 3 feeds and no fourth ground running back to the main panelboard. The feeds are aluminum direct burial. There are grounding rods installed at the detached building. The subpanel is bonded to neutral in the detached garage (definitely a no-no with a 4 wire feed, but this was built in 1988 with no dedicated EGC). As I understand it, NEC allows an exception for the 3 wire system as being grandfather in, providing there are no other metallic connection between the two buildings? First am I correct on this? Now my next question. A gas line was just installed to the detached garage and bonded to the subpanel - I don't know if the gas line is also bonded inside the house, I assume it is, but can't see the line in the walls to verify this, maybe someone did not bond it, which makes two scenarios here. I was ok with the 3 wire bonded electrical sub in the garage until the new metallic gas line was installed. Now that the two buildings are now also bonded through the gas pipe with no dedicated ECG between the sub and main panelboard, what do I do? Do I keep the grounds in the garage that are currently bonded to neutral as they are, or do I separate the ground from neutral at the sub or do I now need to run a ground wire from the sub to the main panelboard? What kind of electrical monkey wrench, if any, has this new gas line introduced? All of this bonding business has always driven me mad. I wish the previous electrician ran a fourth wire in 1988 so I do not have to think about this. I am not 100% comfortable with the old 3 wire feeds without a dedicated ground anyway, so now I am uneasy about this situation.
So leave the subpanel bonded as it is now, do not bond the subpanel, or install a 4th wire (keeping in mind that the ground is frozen solid and it is impossible right now to do any digging and besides digging sucks anyway and I would like to avoid digging anything).
Thanks!
This forum is great and I have been looking at it for years, until today (I just joined, thank you for the great forum) to get some help with the following situation:
I have a sub-panel in a detached garage with 3 feeds and no fourth ground running back to the main panelboard. The feeds are aluminum direct burial. There are grounding rods installed at the detached building. The subpanel is bonded to neutral in the detached garage (definitely a no-no with a 4 wire feed, but this was built in 1988 with no dedicated EGC). As I understand it, NEC allows an exception for the 3 wire system as being grandfather in, providing there are no other metallic connection between the two buildings? First am I correct on this? Now my next question. A gas line was just installed to the detached garage and bonded to the subpanel - I don't know if the gas line is also bonded inside the house, I assume it is, but can't see the line in the walls to verify this, maybe someone did not bond it, which makes two scenarios here. I was ok with the 3 wire bonded electrical sub in the garage until the new metallic gas line was installed. Now that the two buildings are now also bonded through the gas pipe with no dedicated ECG between the sub and main panelboard, what do I do? Do I keep the grounds in the garage that are currently bonded to neutral as they are, or do I separate the ground from neutral at the sub or do I now need to run a ground wire from the sub to the main panelboard? What kind of electrical monkey wrench, if any, has this new gas line introduced? All of this bonding business has always driven me mad. I wish the previous electrician ran a fourth wire in 1988 so I do not have to think about this. I am not 100% comfortable with the old 3 wire feeds without a dedicated ground anyway, so now I am uneasy about this situation.
So leave the subpanel bonded as it is now, do not bond the subpanel, or install a 4th wire (keeping in mind that the ground is frozen solid and it is impossible right now to do any digging and besides digging sucks anyway and I would like to avoid digging anything).
Thanks!