Hi,
I have two different outside feeders that are penetrating building walls:
1. 480V feed from an outdoor substation switchboard to a 480V panel inside a building to feed a few pieces of equipment. This is not a service, this is only for a few tools. Building has other substations inside that feed other equipment.
2. 12KV feed from an outdoor substation to a new 12kv/4160V transformer in a building to then serve one tool. There are no other power sources.
I am looking at NEC Part II and Part III (for item 2 above). These sections focus on disconnecting means to the buildings. Here are my questions:
1. Does this section apply to both cases? I'm guessing yes because it is not a service. I thought it may not because for the 480V feed mentioned above we aren't feeding a distribution board for an entire building, but rather just a few tools.
2. I noticed for under 1000V, there is no requirement for lockable disconnect. Why is this?
3. For the 480V feed, I wanted to use the exception for 225.32 since there are qualified maintenance personnel onsite. The code doesn't clearly delineate how far the disconnect may be outside a building. Our substation switchboard has a 480V breaker outside the building, and it is pretty close (around 20 ft.). But again, it isn't exactly attached to the building itself. And the code doesn't say how far you can go from the exterior or interior. Do I need to even use the exception in this case?
4. For the 480V feed, the type is a standard breaker inside a fenced, locked area only accessible to qualified personnel. Is this ok? I don't see anything that prohibits this since there is no lockable requirement.
5. For the 12 KV feed, just like the 480 its outside in a substation (10 feet from the exterior of the building it serves). But the problem is this is a fuse, not a breaker. I'm assuming this fuse has a switch as well, so that would be the disconnecting means since 225.56(B) mentions fused switches. But Section 225.52(C) requires it to be lockable. So now I need to ensure there are provisions in place. Is there anyway around this? I don't have to have to install a new 12KV disconnect just to make it lockable.
I have two different outside feeders that are penetrating building walls:
1. 480V feed from an outdoor substation switchboard to a 480V panel inside a building to feed a few pieces of equipment. This is not a service, this is only for a few tools. Building has other substations inside that feed other equipment.
2. 12KV feed from an outdoor substation to a new 12kv/4160V transformer in a building to then serve one tool. There are no other power sources.
I am looking at NEC Part II and Part III (for item 2 above). These sections focus on disconnecting means to the buildings. Here are my questions:
1. Does this section apply to both cases? I'm guessing yes because it is not a service. I thought it may not because for the 480V feed mentioned above we aren't feeding a distribution board for an entire building, but rather just a few tools.
2. I noticed for under 1000V, there is no requirement for lockable disconnect. Why is this?
3. For the 480V feed, I wanted to use the exception for 225.32 since there are qualified maintenance personnel onsite. The code doesn't clearly delineate how far the disconnect may be outside a building. Our substation switchboard has a 480V breaker outside the building, and it is pretty close (around 20 ft.). But again, it isn't exactly attached to the building itself. And the code doesn't say how far you can go from the exterior or interior. Do I need to even use the exception in this case?
4. For the 480V feed, the type is a standard breaker inside a fenced, locked area only accessible to qualified personnel. Is this ok? I don't see anything that prohibits this since there is no lockable requirement.
5. For the 12 KV feed, just like the 480 its outside in a substation (10 feet from the exterior of the building it serves). But the problem is this is a fuse, not a breaker. I'm assuming this fuse has a switch as well, so that would be the disconnecting means since 225.56(B) mentions fused switches. But Section 225.52(C) requires it to be lockable. So now I need to ensure there are provisions in place. Is there anyway around this? I don't have to have to install a new 12KV disconnect just to make it lockable.
