aknorth
Member
- Location
- United States
Hey everyone thanks for checking this out and for your help. Had a bit of debate at work here's what we have
So one building is being fed from another building for a run of 400' with 400 amps of capacity at 120/208 3 phase accounting for voltage drop to be no more than 3%, and copper conductors. So the equipment grounding would apply in this case There are two scenarios that would work
1) 3 - 600 kcmil H 1 - 600 kcmil N and 1 - #3 ground
This option did not need to be upsized
2) For economy sake 2 sets of 3 - 300 H 1 - 300 N and 1 - #1/0 ground
This option was upsized from 3 - #4/0 1 - #4/0 and 1 -#3 ground to account for voltage drop and then the ground was increased proportionally
Here's where the problem came in. On one side my colleague says because we didn't have to increase the conductor size for the 600 kcmil even if we use option 2) which would cause us to up size conductors the equipment ground would stay a #3 because the 600 kcmil is your starting pointing and if that didn't need be up-sized then the ground for nay multiple runs would also not need to be up-sized. My position was that you would need to upsize the ground proportionally because you are up-sizing your ungrounded conductors, if you went with option 2. We agree that having to up-size the ground for option two would probably be more ground than the system needs. However it is my position that's what the code requires. What are your thought and opinions?
Thanks
So one building is being fed from another building for a run of 400' with 400 amps of capacity at 120/208 3 phase accounting for voltage drop to be no more than 3%, and copper conductors. So the equipment grounding would apply in this case There are two scenarios that would work
1) 3 - 600 kcmil H 1 - 600 kcmil N and 1 - #3 ground
This option did not need to be upsized
2) For economy sake 2 sets of 3 - 300 H 1 - 300 N and 1 - #1/0 ground
This option was upsized from 3 - #4/0 1 - #4/0 and 1 -#3 ground to account for voltage drop and then the ground was increased proportionally
Here's where the problem came in. On one side my colleague says because we didn't have to increase the conductor size for the 600 kcmil even if we use option 2) which would cause us to up size conductors the equipment ground would stay a #3 because the 600 kcmil is your starting pointing and if that didn't need be up-sized then the ground for nay multiple runs would also not need to be up-sized. My position was that you would need to upsize the ground proportionally because you are up-sizing your ungrounded conductors, if you went with option 2. We agree that having to up-size the ground for option two would probably be more ground than the system needs. However it is my position that's what the code requires. What are your thought and opinions?
Thanks