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Old 11-20-2011, 05:23 PM   #16
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building a main and sub panels for 2 remote buildings


Okay after more searching I think I understand the context of 225.31 and 225.32. If my sub panel in the outbuilding (shop) is 6 or less breakers no main breaker required. If more than six, which it will be and main breaker is required. So I'll have a 125 amp breaker on the service main out by the meter and a 125 amp breaker inside my sub panel in the shop. Am I reading this correctly?

Not sure about that 15 foot requirement I posted above though.

David

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Old 11-20-2011, 05:59 PM   #17
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building a main and sub panels for 2 remote buildings


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Originally Posted by n175h View Post
Okay after more searching I think I understand the context of 225.31 and 225.32. If my sub panel in the outbuilding (shop) is 6 or less breakers no main breaker required. If more than six, which it will be and main breaker is required. So I'll have a 125 amp breaker on the service main out by the meter and a 125 amp breaker inside my sub panel in the shop. Am I reading this correctly?
Yes

Quote:
Not sure about that 15 foot requirement I posted above though.

David
What 15 foot rule, I missed it?

Found it:

Is the "within 15' of the footprint of the building or structure" a local requirement or NEC requirement?

15' in regards to what?

1/0 copper is oversized for a 125 amp panel.

Last edited by Code05; 11-20-2011 at 06:04 PM.
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Old 11-20-2011, 07:22 PM   #18
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building a main and sub panels for 2 remote buildings


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Originally Posted by Code05 View Post
Yes

What 15 foot rule, I missed it?

Found it:

Is the "within 15' of the footprint of the building or structure" a local requirement or NEC requirement?

15' in regards to what?

1/0 copper is oversized for a 125 amp panel.
Here is the 15' reference I found:

And more searching I find NEC 225.31

Disconnecting means must be installed for all ungrounded conductors that supply or pass through a
building (NEC 225.31). The building or structure disconnecting means must be installed either inside or
outside, within 15’ of the footprint of the building or structure. The disconnecting means must consist of no more than six switches or circuit breakers mounted in a single enclosure, in a
group of enclosures, or in or on a switchboard. The allowed disconnects must be grouped and marked to
indicate the load served (NEC 225.34). You should refer to NEC 225 II Section II, “More Than One
Building or Other Structure,” for other outdoor feeder requirements.

Your right, it's not 1/0 wire I need it is #1. Dyslexia
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Old 11-20-2011, 07:57 PM   #19
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building a main and sub panels for 2 remote buildings


Like you I'm researching my electrical for a build I'm in the process of purchasing. Reading your spec you are running thhn under ground, my understanding is you need thwn for water resistance, thhn is not allowed in "wet" areas and buried conduit is concidered " wet". Someone here might be able to confirm or deny that.
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Old 11-20-2011, 08:19 PM   #20
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building a main and sub panels for 2 remote buildings


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Like you I'm researching my electrical for a build I'm in the process of purchasing. Reading your spec you are running thhn under ground, my understanding is you need thwn for water resistance, thhn is not allowed in "wet" areas and buried conduit is concidered " wet". Someone here might be able to confirm or deny that.
Didn't think about it, but I will find out.

David
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Old 11-20-2011, 08:23 PM   #21
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building a main and sub panels for 2 remote buildings


Here you go. I found it on the customer spec sheet for the municipality, so assume it's NEC required. Thanks for the heads up. Seems though than most wire I buy is thhn/thwn dual designation and should be easy to find at any hardware store.

David

PVC conduit must be approved as electrical conduit.
Other types, such as PVC plumbing pipe, are not
acceptable. Standard insulated conductors may be
pulled inside the PVC. These single conductors must
have a “W” (water-resistant) in the designation
stamped on the jacket of the wire. Examples of such
designations include: THWN, XHHW, etc. Type
“Romex” or Non-Metallic Cable (NM-B) cannot be run
inside underground conduit, because the outer jacket
of the NM-B is not rated for wet locations.

Last edited by n175h; 11-20-2011 at 08:32 PM.
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Old 11-20-2011, 08:43 PM   #22
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building a main and sub panels for 2 remote buildings


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Originally Posted by n175h View Post
Where do GFCI plugs come into play in this building. Is this a "shop" or "garage"? Do I need to choose my wording carefully on my permit application?

David
GFCI probably required.

210.8(A)(2) Garages, and also accessory buildings that have a floor
located at or below grade level not intended as habitable
rooms and limited to storage areas, work areas,
and areas of similar use
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Old 11-20-2011, 08:45 PM   #23
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building a main and sub panels for 2 remote buildings


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Originally Posted by n175h View Post
Didn't think about it, but I will find out.

David
Modern THHN is dual rated as THWN.
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Old 11-20-2011, 08:49 PM   #24
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building a main and sub panels for 2 remote buildings


Quote:
Originally Posted by n175h View Post
Here is the 15' reference I found:

And more searching I find NEC 225.31

Disconnecting means must be installed for all ungrounded conductors that supply or pass through a
building (NEC 225.31). The building or structure disconnecting means must be installed either inside or
outside, within 15’ of the footprint of the building or structure. The disconnecting means must consist of no more than six switches or circuit breakers mounted in a single enclosure, in a
group of enclosures, or in or on a switchboard. The allowed disconnects must be grouped and marked to
indicate the load served (NEC 225.34). You should refer to NEC 225 II Section II, “More Than One
Building or Other Structure,” for other outdoor feeder requirements.
That is not NEC or IRC, where did you get this? Local amendment? It mixes several NEC/IRC sections together with added rules.

Last edited by Code05; 11-20-2011 at 08:57 PM.
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Old 11-20-2011, 08:52 PM   #25
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building a main and sub panels for 2 remote buildings


Quote:
Originally Posted by n175h View Post
Here you go. I found it on the customer spec sheet for the municipality, so assume it's NEC required. Thanks for the heads up. Seems though than most wire I buy is thhn/thwn dual designation and should be easy to find at any hardware store.

David

PVC conduit must be approved as electrical conduit.
Other types, such as PVC plumbing pipe, are not
acceptable. Standard insulated conductors may be
pulled inside the PVC. These single conductors must
have a “W” (water-resistant) in the designation
stamped on the jacket of the wire. Examples of such
designations include: THWN, XHHW, etc. Type
“Romex” or Non-Metallic Cable (NM-B) cannot be run
inside underground conduit, because the outer jacket
of the NM-B is not rated for wet locations.
Correct. However, some cables such as UF and USE are wet rated.
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Old 11-20-2011, 10:00 PM   #26
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building a main and sub panels for 2 remote buildings


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Originally Posted by Code05 View Post
That is not NEC or IRC, where did you get this? Local amendment? It mixes several NEC/IRC sections together with added rules.
Municipal spec sheet for homeowners. Not my city, however.

David
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Old 11-20-2011, 10:20 PM   #27
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building a main and sub panels for 2 remote buildings


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Municipal spec sheet for homeowners. Not my city, however.

David
Then it is not applicable unless adopted by your jurisdiction/area.

What is your location? You may have a statewide policy that is easy to access.
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Old 11-21-2011, 10:08 AM   #28
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building a main and sub panels for 2 remote buildings


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Then it is not applicable unless adopted by your jurisdiction/area.

What is your location? You may have a statewide policy that is easy to access.
south Texas near San Antonio. No statewide policy that I know, but my local city has been working under the 2008 NEC. Not sure if they have adopted the 2011 version. I haven't seen any new "electric ordinances" posted on their website. It's usually behind anyway. I mainly have to satisfy the inspector. He is a retired plumber by trade and knows little about electrical. However, it is important that I prove to him my competence. They have been pretty easy to work with in the past.

The utility company is very accommodating. The last time I did this I had to dig the trench from their pole to my service entrance and provide a deeded easement. I think the ditch had to be 44" deep. They are extremely busy, however because of the all the oil drilling in south Texas. It takes six weeks to get a service drop off their transformer. I just went through this on a commercial building I built last year.

David

Last edited by n175h; 11-21-2011 at 10:24 AM.
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Old 11-21-2011, 10:43 AM   #29
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building a main and sub panels for 2 remote buildings


Quote:
Originally Posted by n175h View Post
And more searching I find NEC 225.31

Disconnecting means must be installed for all ungrounded conductors that supply or pass through a
building (NEC 225.31). The building or structure disconnecting means must be installed either inside or
outside, within 15’ of the footprint of the building or structure. The disconnecting means must consist of no more than six switches or circuit breakers mounted in a single enclosure, in a
group of enclosures, or in or on a switchboard. The allowed disconnects must be grouped and marked to
indicate the load served (NEC 225.34). You should refer to NEC 225 II Section II, “More Than One
Building or Other Structure,” for other outdoor feeder requirements.

For some reason I'm not differentiating this as to exactly where THIS panel in NEC 225.31 is. Is this 6 space limit for the service main adjacent my meter can? Or is this 6 space limit at the panel on the inside wall of my proposed building? My interpretation is that the 6 space limit is at the service main (which was my planned enclosure), and I can have up to 6 separate buildings powered from it.

Is the "within 15' of the footprint of the building or structure" a local requirement or NEC requirement?
This article is in regards to disconnecting means. For example. A panel with 6 breaker handles or less could be installed without a main disconnect. The 6 or less breaker handles can be the disconnect. This includes your first building. If you have less than 6 breaker handles (requires no more than 6 throws of the hand) a main breaker can be excluded. I do not recommend this as future additions to the panel can exceed 6 handles. The 15' rule is only to keep the disconnecting means as close to the intended structure as possible. An example of this would be a pedestal service or disconnect for a trailer. (shown below)

Quote:
Originally Posted by n175h View Post
It's customary around here to hang a meter can and pipe over to the main panel. I can't remember seeing any all in one enclosures. It doesn't mean it can't be done. It's between me and the utility service provider. David
The service provider is only responsible for the installation of the meter and the other requirements in your jurisdiction. You are responsible to install this service and subsequent sub panel or main service panel to NEC standards.
A meter main allows you to install your feeder to the second building without entering or passing through the first building. It is to assist in the addition of the second building.

In the picture below are examples of two points I made. First is the "footprint of the structure". this picture is a meter main pedestal mount. The distance from the disconnect for the barn is in the footprint of the barn, making it compliant.
Second. You cannot see inside the meter main (sorry I did not have a picture handy). But inside is the meter housing hardware and a panel. A panel with just a few breaker slots. Two of these slots could be used for your second building. You then also have an extra few for outside uses. Very handy for hot tubs, pools, another structure ect....... For any power requirements outside.

I am not trying to confuse you. There are more than one (1) compliant way to to this job. Good Luck.
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Old 11-25-2011, 09:12 PM   #30
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building a main and sub panels for 2 remote buildings


My service provider for this project will be AEP/Texas. A bit more searching from AEP Texas website doesn't have an installation application for an underground service not attached to the wall of a dwelling other than a mobile home installation. AEP cites an NEC section (without a section number) that recommends the service on the customer's remote meter pedestal shall be within 30' of the mobile home. It did not say require.

My proposal for my service main and meter will be 27' from my out building/garage. However, when I build my house at this location in two years, this service main will be 80' from the dwelling (house) sub panel, but it will be within sight. My stub for my sub panel on the house was planned to be inside the house with nothing hanging on its outside wall. Am I going to run into a problem with this?

A solution would be to place a sub panel on the outside wall fed by the service main 80' away, then let it feed another sub panel inside the home, but is that necessary? It's another panel, more wire, and more connections to make.

I have not contacted AEP yet, nor have I presented my proposal to our AHJ. I'm lining all my ducks first before we meet.

David

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