Detached Garage

[Npstewart]

Im working on a large house with a detached garage. The detached garage is required to have a few branch circuits for the lights, receptacles & opener etc.

Would it be possible to feed these circuits from a panel in the main house?

 

[kwired]

Im working on a large house with a detached garage. The detached garage is required to have a few branch circuits for the lights, receptacles & opener etc.

Would it be possible to feed these circuits from a panel in the main house?

Only with a single circuit or a multiwire branch circuit, any more than that and you will need a feeder and branch circuits will need to originate in garage.

See 225.30.

 

[bphgravity]

No, you must meet the provisions of Section 225.30 of the NEC:

225.30 Number of Supplies. A building or other structure
that is served by a branch circuit or feeder on the load side
of a service disconnecting means shall be supplied by only
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.
Where a branch circuit or feeder originates in these
additional buildings or other structures, only one feeder or
branch circuit shall be permitted to supply power back to
the original building or structure, unless permitted in
225.30(A) through (E).
For the purpose of this section, a multiwire branch circuit
shall be considered a single circuit.

So, you have three (3) options.

1. New service at the separate structure.
2. A single feeder supplying a panelboard in the separate structure.
3. A single branch circuit supplying the separate structure.

Please keep the provisions of Section 250.32 in mind as well...

 

[Npstewart]

Ok. Just a couple more questions.

If I went with option #2, I wouldn't need another ground rod correct? Running just the EGC would be adequate?

 

[Npstewart]

Sorry, didn't see the last line of your post. ....250.32

 

[hurk27]

There is one other method but it depends upon what meter was used at the house, you said a very large house so if you have a 320 meter, you can get double lugs for it you can just run a 3 wire service entrance from these double lugs on the load side of the meter to the garage and install a main breaker panel in the garage just like you would do a service on a house, but with no meter on the garage, I do this all the time for out buildings that need more then one circuit, and it doesnt require loading the house panel. I think milbank make a 200 amp meter base with double load side lugs also but they are hard to find.

 

[Npstewart]

Thats a really good idea. I do have a 320 meter, ill be finishing it up today and ill see how it works out best. Thanks for the help everyone.

 

[George Stolz]

I'd imagine that a feeder from the house's panel would be a cheaper superior design. Branching the service for this task seems a little fruity and would complicate changing needs in the future, IMO.

 

[iwire]

I'd imagine that a feeder from the house's panel would be a cheaper superior design. Branching the service for this task seems a little fruity and would complicate changing needs in the future, IMO.

Full capacity of the service, less conductors, less breakers. The same GES, and service rated disco requirements.

To me it sounds better, less costly and have more flexibility for changes.


Other than that we agree. :lol:

 

[kwired]

What is wrong with 200 amp meter socket, conductors sized for calculated load (of 200 amps max) for both structures. From socket go to a terminal or splice box if you can't come up with meter with double lugs and go separate ways from there?

 

[hurk27]

What is wrong with 200 amp meter socket, conductors sized for calculated load (of 200 amps max) for both structures. From socket go to a terminal or splice box if you can't come up with meter with double lugs and go separate ways from there?

Done it that way also.

 

[kwired]

Done it that way also.

It may be easier or even cost less to use 320 socket but that is an option.

A 200 class meter will plug into a 320 socket won't it? If not that could bring up issue with POCO. The supply to the 320 socket will not have to be more than 200 amp conductor if calculated load is not over 200 amps. Some people have a hard time realizing that.

 

[hurk27]

It may be easier or even cost less to use 320 socket but that is an option.

A 200 class meter will plug into a 320 socket won't it? If not that could bring up issue with POCO. The supply to the 320 socket will not have to be more than 200 amp conductor if calculated load is not over 200 amps. Some people have a hard time realizing that.

At the cost of wire these days running three conductors instead of 4 can be a great savings, and since no disconnect or OCPD is required at the supply end there is another savings, and the fact in most cases running another conduit out of the meter can into the ground can be much easier then trying to thread a conduit back into the house panel, and yes a CL200 meter will fit everything from a 100 amp to 320 amp 4 jaw meter base and in this area is the meter used.

Each job has to be evaluated as to which of the above methods saves the customer the most and can be accomplished easiest.