Spare Capacity Service and Panel

[NEC User]

I've been taught that for new construction projects there is a code requirement for having spare capacity. For example, for a 100A service for a new construction project with only one panel, I can only load the panel up to 80A. What code section is this indicated in?


Also, if the panel is a 42 pole panel. Can I load install equipment on all 42 poles or is there a code requirement that for new construction there needs to be spare physical space within the panel too?

 

[MasterTheNEC]

@malteser

I believe what you are thinking about is Section 90.8(A) in the 2014 NEC. Nothing in 90.8(A) mandate the added space, it just recommends it so to speak. In todays ever changing capacity world it is always a good design strategy to consider this but not a mandate by the NEC. If you would like to install 42 circuits ( remember that the 42 circuit limitation, with one exception, has been removed in the NEC) that's your choice. Just remember that a panelboard is designed to hold the specific amount of OCPD's as denoted by the specifications....so keep that always in your mind and review 408.36 for more details on that one 42 OCPD limitation... which I will gladly explain if you choose to inquire about later.

 

[Smart $]

Myth.

There are instances where you cannot use all breaker spaces if the number of branch circuits required is less than the number of circuits actually used. Can't recall the exact section number... perhaps 210.2x something.

 

[MasterTheNEC]

The consideration is load. The number of OCPD's established by the manufacturer will not change. The load will be the defining factor but how you distribute it is your choice as long as it is distributed equally in terms of branch circuits. I believe possibly what "smart" is referring too is Section 210.11(B) but I could be wrong but honestly I don't believe it plays a big weight on the question itself.

 

[Smart $]

Myth.

There are instances where you cannot use all breaker spaces if the number of branch circuits required is less than the number of circuits actually used. Can't recall the exact section number... perhaps 210.2x something.

Less should be more.

 

[NEC User]

I could not find any New York State or New York City amendment stating panels with over 42 poles are permitted or not allowed. Is it safe to assume that I can use a 72 Pole panel in New York City?

 

[Smart $]

The consideration is load. The number of OCPD's established by the manufacturer will not change. The load will be the defining factor but how you distribute it is your choice as long as it is distributed equally in terms of branch circuits. I believe possibly what "smart" is referring too is Section 210.11(B) but I could be wrong but honestly I don't believe it plays a big weight on the question itself.

Had time to look it up... 210.11(A) is where the minimum number of branch circuits is required... according to calculated load. Connected load is all that is required to be supplied and may not require as many circuits as determined under this section. BUT... the determined minimum number of circuits must remain available, whether used or not.

 

[Smart $]

I could not find any New York State or New York City amendment stating panels with over 42 poles are permitted or not allowed. Is it safe to assume that I can use a 72 Pole panel in New York City?

IMO, it is hardly ever safe to assume anything in this trade...

 

[MasterTheNEC]

IMO, it is hardly ever safe to assume anything in this trade...

Dude....I simply can't disagree with that statement !

@malteser

if they make a panelboard with 72 spaces then by dang you can use it, just consider the actual load first. Unless of course the area you are installing it in still lags back to the 2005 NEC...which could be the case in New York...sadly.