225.30 and 230.2: An oddity?

[charlie b]

Can you have a 208/120V service into a building and also have a 480/277V feeder from a separate building? My instincts say no, but I don't see the words that say no in either article.

 

[LarryFine]

If it's not prohibited, it's permissible.

 

[charlie b]

I can't argue with that. But it just seems wrong.

However, this project's designer has some other rethinking to do. It's not just one 480V feeder from bldg 1 to bldg 2, but two such feeders. Also, there are 2 branch circuits from bldg 2 back to bldg 1.

 

[tom baker]

The branch ckts are an issue.
As you know it’s allowable to have multiple services and feeders, but disconnects must be grouped. Are the branch circuits an emergency source?

 

[wwhitney]

Can you have a 208/120V service into a building and also have a 480/277V feeder from a separate building? My instincts say no, but I don't see the words that say no in either article.

Certainly you can, as those two supplies are different voltages, and both 225.30 and 230.2 have allowances for multiple supplies of different characteristics.

The more interesting question is whether you can have a 208Y/120V service into a building and also a 280Y/120V feeder from a separate building. 230.2 refers only to the number of services, and 225.30 refers only to the number of branch circuit and feeders. So it appears that any building can have 1 supply of each type.

I submitted PIs for the 2026 NEC to 225.30 and 230.2, one set to make the two section coordinate to prohibit two supplies, one by a service and one by a branch circuit or feeder, absent one of the allowances listed in the section; the other PI made a minimal change to make it slightly clearer that any building may have one supply of each.

Amazingly all the PIs were rejected, and the panel statements in the rejections did not even comment on the underlying question. It appeared the CMP in charge of 225 would not even comment on services, and the CMP in charge of 230 would not even comment on feeders or branch circuits. So there is nobody to address the question of how the two articles interact with respect to supplying a building.

My take away is that the direct reading applies, and any building may have one supply that is a service and one supply that is a branch circuit or feeder, without restriction. If one of the conditions in 225.30 and/or 230.2 applies, then the building may have multiple supplies of the applicable type in addition to one or more supplies of the other type.

Cheers, Wayne

 

[LarryFine]

Theoretical comparison:

Suppose you had, say, four condominiums that share a single, detached, four-car parking garage.

Could each parking bay be supplied with a light and receptacle from the owners' respective units?

 

[charlie b]

Are the branch circuits an emergency source?

No. Each serves a mechanical pump. There are no 700 loads other than egress lights.

 

[wwhitney]

However, this project's designer has some other rethinking to do. It's not just one 480V feeder from bldg 1 to bldg 2, but two such feeders. Also, there are 2 branch circuits from bldg 2 back to bldg 1.

If both feeders originate in the same supply equipment in building 1, then it is allowed under 2020 and 2023 NEC 225.30(B) (which allowance is not present in earlier NECs). Likewise, if both branch circuits originate in the same supply equipment in building 2, that it is allowed under the same section.

Cheers, Wayne

 

[charlie b]

The more interesting question is whether you can have a 208Y/120V service into a building and also a 280Y/120V feeder from a separate building. 230.2 refers only to the number of services, and 225.30 refers only to the number of branch circuit and feeders. So it appears that any building can have 1 supply of each tytype.

That is essentially the same issue that I am hoping to resolve here. Two voltages are OK, but is one service plus one feeder also OK?

 

[Dennis Alwon]

The more interesting question is whether you can have a 208Y/120V service into a building and also a 280Y/120V feeder from a separate building. 230.2 refers only to the number of services, and 225.30 refers only to the number of branch circuit and feeders. So it appears that any building can have 1 supply of each type.

I had this same issue come up on me many moons ago and I submitted the question to NC yearly conference on the code. The panel is made up of some big wigs from the nec cmp.

The decision, as I recollect, was that it was compliant

 

[wwhitney]

That is essentially the same issue that I am hoping to resolve here. Two voltages are OK, but is one service plus one feeder also OK?

Yes, there is no language prohibiting it. Article 230 covers the numbers of services; Article 225 covers the number of branch circuits and feeders; and there's nothing in either article that would case one to affect the other.

Cheers, Wayne

 

[Dennis Alwon]

I had this same issue come up on me many moons ago and I submitted the question to NC yearly conference on the code. The panel is made up of some big wigs from the nec cmp.

The decision, as I recollect, was that it was compliant

In our situation we had a detached garage that had a service feeding the garage apt on the second floor but the actual feeder for the garage itself came from the existing house ,

 

[jaggedben]

Can you have a 208/120V service into a building and also have a 480/277V feeder from a separate building? My instincts say no, but I don't see the words that say no in either article.

My instincts say it's fine. What safety issue is presented by a feeder and a service that isn't presented by two feeders or two services, or vice versa?

...
Amazingly all the PIs were rejected, and the panel statements in the rejections did not even comment on the underlying question. It appeared the CMP in charge of 225 would not even comment on services, and the CMP in charge of 230 would not even comment on feeders or branch circuits. So there is nobody to address the question of how the two articles interact with respect to supplying a building.

...

 

[shortcircuit2]

Theoretical comparison:

Suppose you had, say, four condominiums that share a single, detached, four-car parking garage.

Could each parking bay be supplied with a light and receptacle from the owners' respective units?

I would say yes with grouping of the disconnects...