Number of feeders suppling a building

[Rob Trumbull]

I have a 800amp. service free standing approx. 50'from a building. It would be within sight of the building, although a parking lot is in between the two. The designer is suppling the building with 6 sets of feeders to different locations within the structure. There is no disconnecting means for these feeders other than whats in the main service. Does this comply with section 225-30 of the 2002 NEC

 

[iwire]

Re: Number of feeders suppling a building

Rob at first glance no it does not comply but that is a large assumption.

Perhaps the designer feels that the installation meets one of the sections in 225.30(A) through (E).

 

[charlie b]

Re: Number of feeders suppling a building

I agree that it does not comply. But just to be clear, the issue is not that each of the individual feeders is missing a separate disconnecting means. The issue is that the designer is attempting to power a single building with more than one feeder.

 

[iwire]

Re: Number of feeders suppling a building

Originally posted by charlie b:
The issue is that the designer is attempting to power a single building with more than one feeder.

Charlie you have left me confused.

The number of supplies is just what 225.30(A) through (E) addresses and you certainly can have more than one supply under the correct circumstances.

The lack of disconnecting means I overlooked.

Both the number of supplies and the lack of disconnects can be overcome by documented safe switching procedures.

All that aside IMO it is more likely that the designer does not know the NEC.

 

[charlie b]

Re: Number of feeders suppling a building

No, Bob. You and I are on the same page. Perhaps I just wasn't clear. I wanted to confirm that that the issue (the question) had to do with multiple feeders to a building, and not with the lack of disconnects. Once we confirm that that is the question, then we look in the code (i.e., to see if it is acceptable for a building to have multiple feeders). I agree with you, in that it is sometimes OK, as described in the article you cited.

 

[Rob Trumbull]

Re: Number of feeders suppling a building

Non of the feeders suppling the building in question meets the special conditions noted in 225-30 or 230-2.

 

[charlie b]

Re: Number of feeders suppling a building

Then I think you have your answer: Throw a flag on the play.

 

[hurk27]

Re: Number of feeders suppling a building

Are each of these feeders from a separate meter?
Is there a fire wall that might make each section of building a separate structure?
Is there one disconnect before the meters or is there a disconnect for each feeder? I feel that if these conductors have not entered a building yet and are part of a service remotely located the disconnects at the service are not required and then the feeders would turn into service entrance cables which would treat each panel as service equipment. This would allow 230.40 exception 1 to apply which would allow this installation if the panels had main breakers and were located as close to as possible to the entrance of the SEC's ????
This is only my view.

[ August 30, 2005, 07:39 PM: Message edited by: hurk27 ]

 

[Rob Trumbull]

Re: Number of feeders suppling a building

The 800 amp. service has a main disconnect. Each feeder has a 100amp. disconnect at the service. No disconnect at point of entry to building. There are no "main disconnect" in the sub panels. The building is one occupancy (senior housing-2 stories) The panels are in three seperate locations in the building.Two upstairs. Two in the downstairs hallway and two in a electrical equipment room.

 

[sandsnow]

Re: Number of feeders suppling a building

I think that first you have to define the 800 amp service as a structure. From the description, it sounds like a stand up switchboard sitting on a concrete slab. You would construct the slab and then install the switchboard on top of it. If you are not comfortable with calling the 800 amp service a structure, then 225.30 would not apply since you only have one building or structure on the property. I would find it hard to argue that one in favor of it being a structure.

Also 225.32 allows the disconnecting means to be outside the building and goes on to say it shall be at a readily accessible location nearest the point of entrance. Well if the service is outside then you don't have a point of entrance. There is also no distance given for how far away from the building it is allowed to be. It does not say mounted on the building, just outside.

If I install the service on the building I'm ok right? So if I install the service 6 inches away, am I ok? What about 12 inches? What about 6 feet?

After all that, I think this is a an issue of the AHJ making an interpretation of the rules. I believe the code is defecient here and does not effectively address this possibility of installation.

There is still the issue of the grounding electrode required at the building and bonding of water, etc. These would have to be connected to the service.