Garage sub panels

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george t. everett

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New York
Wiring a dwelling with a detached garage and studio apartment above. Owner wants the garage on a generator, but not the apartment. Can I run 2 sub-feeders to the garage, 1 from the main panel and 1 from the generator panel? Do the disconnects need to be grouped at the garage? Thanks for any help.
 
If you run a feed from the gen what will supply the garage when the gen is not running?

Is this a commercial property?
How big is the apartment?

In general you are only permitted to have one to a structue.

???


Charlie
 
George, see Part II of Article 225. (I'm not being a smart aleck, that whole part is relevant to how you proceed. ;) )

The most specific answer to your question is yes, it is permitted. Ensure that the disconnect to the dwelling unit is 100A (225.39(C)), the disconnect to the garage is 60A (225.39(D)), and that they are grouped (225.34(A)) and identified (225.37).

Edit to add: You will need to have a grounding electrode system per 250.32(A), so with the two neutrals for the two feeders, you will need to install an EGC for the feeders to the detached structure, and comply with 250.32(B)(1). See this recent thread for more info on the matter. :)
 
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Sounds to me like you've got it right.
IMO...225.30(A) Special Conditions allows you to run 2 feeders to the detached building.
The (2) subs in the detached building need to be grouped together.
Each sub will need a main breaker if there are over 6 breakers total in the panels (combined).
Pay heed to 300.3(B)
steve
 
225.30 Number of Supplies.
Where more than one building or other structure is on the same property and under single management, each additional building or other structure served that is on the load side of the service disconnecting means shall be supplied by one feeder or branch circuit unless permitted in 225.30(A) through (E). For the purpose of this section, a multiwire branch circuit shall be considered a single circuit.
(A) Special Conditions. Additional feeders or branch circuits shall be permitted to supply the following:
(1) Fire pumps
(2) Emergency systems
(3) Legally required standby systems
(4) Optional standby systems
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The 'extra' feeder from the generator is specifically allowed by 225.30(A)(4)
 
georgestolz said:
77's got a good point. You might be save money buying less conductor, if you install one feeder and put the TS at the detached garage. :cool:
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Now all he'll need is a second generator. :eek:
 
georgestolz said:
He never said the main house would see any benefit from the generator. :p
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Maybe he did:
george t. everett said:
There will be a transfer switch in the main house. The sub-feed to garage will come out of the gen panel in basement.
Click to expand...
 
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