Detached garage grounding

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Anderman123

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Gents,

I'm in an area using NEC 2014. This is already built, I'm just looking at for a code compliance exercise.

I have a detached garage around 7' from the main building (not a house). The grounding electrode is in between the two buildings. I have several circuits going to the garage from the main panel. Can I consider the building and garage as a structure, since they will be using the same grounding electrode? Or does the garage require its own panel?
 
Anderman123 said:
Gents,

I'm in an area using NEC 2014. This is already built, I'm just looking at for a code compliance exercise.

I have a detached garage around 7' from the main building (not a house). The grounding electrode is in between the two buildings. I have several circuits going to the garage from the main panel. Can I consider the building and garage as a structure, since they will be using the same grounding electrode? Or does the garage require its own panel?
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By definition it should be a separate structure. Although I think you could be able to just tap into the GES that is already there and run a GEC to your detached garage.
 
Dsg319 said:
By definition it should be a separate structure. Although I think you could be able to just tap into the GES that is already there and run a GEC to your detached garage.
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The detached garage does not have its own panel, just circuits from the main panel. How would that work?
 
Anderman123 said:
The detached garage does not have its own panel, just circuits from the main panel. How would that work?
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If you have more than 1 circuit or more than 1 MWBC the building has to have a GES. I would assume to just attach it to building steel.

We’ll see what others have to say.
 
Dsg319 said:
If you have more than 1 circuit or more than 1 MWBC the building has to have a GES. I would assume to just attach it to building steel.

We’ll see what others have to say.
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The GES will be the same one as the main building. The building is wood and concrete.
 
Anderman123 said:
Gents,

I'm in an area using NEC 2014. This is already built, I'm just looking at for a code compliance exercise.

I have a detached garage around 7' from the main building (not a house). The grounding electrode is in between the two buildings. I have several circuits going to the garage from the main panel. Can I consider the building and garage as a structure, since they will be using the same grounding electrode? Or does the garage require its own panel?
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You also need to take a look at 225.30. The following is from the 2014 NEC. I see it at a separate structure.
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. ...
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Anderman123 said:
Seems the only way to fix it would be to install a subpanel. Was hoping for another option.
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Or to save money from buying an actual sub panel with branch breakers that the circuits already have, get a junction box with a ground bus bar to terminate all your EGC and your grounding electrode conductor.
 
Likely a sub-panel is your answer, however, your OP does not actually identify the type facility. You might note 225.30(E) in the event it is applicable.
 
For a separate building the options are
1. Install a single branch circuit or MWBC, 250.32 EX, 225.30
and a disconnecting means (2 pole snap switch) 225.31 and 32
2. Install a feeder panel, and grounding electrode system
250.32
Note your feeder must be a 4 wire, and the neutral and grounds are separate
If you main building and separate building ground rods are closer than 6ft they are to be bonded together
 
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tom baker said:
2. Install a feeder panel, and grounding electrode system
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Be sure that this includes doing away with the individual circuits, redirecting them to a sub-panel in the garage itself, and installing a single feeder large enough for the entire garage.

This is what should have been done even if the existing work is decades old.

Just curious, how are those several circuits physically run?
 
Dsg319 said:
Or to save money from buying an actual sub panel with branch breakers that the circuits already have, get a junction box with a ground bus bar to terminate all your EGC and your grounding electrode conductor.
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That is not allowed. see my reply above
 
marmathsen said:
Since this is just an exercise, how do you define a separate building? Could you consider it the same building if you build a breezeway roof between them and attached it to both structures?

Rob G
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A breezeway connected on both ends makes it one structure.
 
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