Minimum supply to a residential occupancy

[Smart $]

a "service feeder" would be kin to a "bear elephant" or "kangaroo turtle"..
can't be both.
Therein lies the problem. If its a service Art 230 has a minimum size of 100 amp for a SF dwelling. If it's an outside Art 225 has a minimum in 225.39.
If it's an inside feeder, I see no minimum other than as required by Art 220,

Q1: If you have a multifamily dwelling with separate service disconnecting means for each, does 230.79(C) apply to those disconnects?

Q2: If you have a multifamily dwelling with single service disconnecting means, then supply meters and outside disconnects for each unit, does 225.39(C) apply to those disconnects?

 

[iwire]

Q1: If you have a multifamily dwelling with separate service disconnecting means for each, does 230.79(C) apply to those disconnects?

I will go with yes 230.

Q2: If you have a multifamily dwelling with single service disconnecting means, then supply meters and outside disconnects for each unit, does 225.39(C) apply to those disconnects?

I will go yes, 225

 

[augie47]

Q1: If you have a multifamily dwelling with separate service disconnecting means for each, does 230.79(C) apply to those disconnects?

We are getting into one of those "word games" that accompanies most Code discussions
In answer to Q1, I think an argument can be made that 230.79(C) would not apply due to the NEC definition: Dwelling, One-Family.A building that consists solely of one dwelling unit.
If the "building" is a multi-family it may consist of many dwelling units but it (the building) is not a One Family Dwelling. 230.79 does not say "One family Dwelling Unit"

Q2: If you have a multifamily dwelling with single service disconnecting means, then supply meters and outside disconnects for each unit, does 225.39(C) apply to those disconnects?

If the disconnects are outside but the feeders are not, then I don't see 225 applying at all.

I think there are a lot of fine lines and I agree with Dennis that the best bet would be to check with the AHJ.
As with all postings here mine is an opinion and with the wording as tricky as it is I don't wish to get into a long discussion.

 

[iwire]

Q1: If you have a multifamily dwelling with separate service disconnecting means for each, does 230.79(C) apply to those disconnects?

Q2: If you have a multifamily dwelling with single service disconnecting means, then supply meters and outside disconnects for each unit, does 225.39(C) apply to those disconnects?

Let me ask you one, I will describe a typical condo or apartment building in my area.

Pad-mount transformer outside, service point at the secondary terminals > underground run into the buildings electrical room > single service disconnecting means > module meter stacks with breakers for each unit.

What is the NEC minimum disconnect / feeder size for each individual unit?

 

[Smart $]

I will go with yes 230.



I will go yes, 225

We are getting into one of those "word games" that accompanies most Code discussions
In answer to Q1, I think an argument can be made that 230.79(C) would not apply due to the NEC definition: Dwelling, One-Family.A building that consists solely of one dwelling unit.
If the "building" is a multi-family it may consist of many dwelling units but it (the building) is not a One Family Dwelling. 230.79 does not say "One family Dwelling Unit"



If the disconnects are outside but the feeders are not, then I don't see 225 applying at all.

I think there are a lot of fine lines and I agree with Dennis that the best bet would be to check with the AHJ.
As with all postings here mine is an opinion and with the wording as tricky as it is I don't wish to get into a long discussion.

I'm with you Gus. Sorry, Bob.

The (C) of each section does not apply. However, I believe (D) of the respective sections apply accordingly to both scenarios. That is, the minimum unit disconnect cannot be less than 60A. As to Q2 in particular, the disconnect and the start of the feeder are both outside.

 

[iwire]

I'm with you Gus. Sorry, Bob.

No need to be sorry that you are wrong.

Kidding.


I am going to stick with my original answer but it is nothing I am going to fight over, it will be an AHJ call.

Q1: If you have a multifamily dwelling with separate service disconnecting means for each, does 230.79(C) apply to those disconnects?

The building may well be a MFD but the service disconnecting means in question is only supplying a SFD.

 

[Smart $]

No need to be sorry that you are wrong.

Kidding.

I am going to stick with my original answer but it is nothing I am going to fight over, it will be an AHJ call.

The building may well be a MFD but the service disconnecting means in question is only supplying a SFD.

If I am wrong, I am more sorry than I thought... :lol:

I use to think same as you, but have long since changed my disposition because of what Gus pointed out about the definition of "Dwelling, One-Family." Note the titles of 225.39(C) and 230.79(C) are "One-Family Dwellings."

 

[mbrooke]

Let me ask you one, I will describe a typical condo or apartment building in my area.

Pad-mount transformer outside, service point at the secondary terminals > underground run into the buildings electrical room > single service disconnecting means > module meter stacks with breakers for each unit.

What is the NEC minimum disconnect / feeder size for each individual unit?

Exactly my question

 

[Smart $]

Let me ask you one, I will describe a typical condo or apartment building in my area.

Pad-mount transformer outside, service point at the secondary terminals > underground run into the buildings electrical room > single service disconnecting means > module meter stacks with breakers for each unit.

What is the NEC minimum disconnect / feeder size for each individual unit?

Calculated load with continuous factored at 125%.

 

[augie47]

Not that any of us have changed our minds,... but we went this road...pretty much to the same destination it seems, a year ago.
http://forums.mikeholt.com/showthread.php?t=160116&highlight=apartment+feeder

 

[iwire]

If I am wrong, I am more sorry than I thought... :lol:

I use to think same as you, but have long since changed my disposition because of what Gus pointed out about the definition of "Dwelling, One-Family." Note the titles of 225.39(C) and 230.79(C) are "One-Family Dwellings."

In that case I will have to agree to what the words say (and can be enforced) but I do not believe that is the intent.

 

[iwire]

Calculated load with continuous factored at 125%.

That is something we agree on.

 

[mbrooke]

So it looks like part of it involves asking the AHJ.

Since the dwelling table doesn't apply, can SER be used on the 75*C column?

 

[Smart $]

In that case I will have to agree to what the words say (and can be enforced) but I do not believe that is the intent.

That's exactly what I used to think... :blink:

For all the more difference there is between one-, two- and multifamily dwellings, I wish they would just condense it into dwelling unit(s) and have some provision based on number of or square footage of bedroom(s) per dwelling unit.

 

[Dennis Alwon]

So it looks like part of it involves asking the AHJ.

Since the dwelling table doesn't apply, can SER be used on the 75*C column?

That would depend on a few factors one being what code cycle. Read 338.10(B)

 

[mbrooke]

That would depend on a few factors one being what code cycle. Read 338.10(B)

2014, but will read up on it. Thanks!

 

[Smart $]

2014, but will read up on it. Thanks!

What are you referring to when you say dwelling table doesn't apply? And why not?

 

[mbrooke]

What are you referring to when you say dwelling table doesn't apply? And why not?

My take is the dwelling table does not apply to condominiums or in this case what I consider none services.

 

[Smart $]

My take is the dwelling table does not apply to condominiums or in this case what I consider none [?] services.

If you are referring to 310.15(B)(7), it may not apply to a combined service, but it could apply to dwelling unit feeders...

 

[mbrooke]

If you are referring to 310.15(B)(7), it may not apply to a combined service, but it could apply to dwelling unit feeders...

Even a multi family?