Two circuits to a detached garage

Status
Not open for further replies.
L

Leespark57

Senior Member
Location
Boston, MA, USA
I'm perplexed with an unusual scenario. A 2 family home with no common area and no common panel. There is a detached 2 car garage which is shared by both units (each has there own side). They want to run 2 circuits to the garage (one circuit from each unit) to feed 2 garage door openers and 2 receptacles. It seems this would be prohibited since it is not a MWBC as required by 225.30. Any thoughts?
Thanks
 
I think I could successfully put forth a case for applying 225.30(B)(1). Neither homeowner has access to the other homeowner's service equipment, and neither service panel is in the common garage.
 
I would just run a 30-amp subfeed off one of the panels, then a small subpanel in the garage to feed the opener and lighting circuits. The cost of the electricity used is negligible, as long as only lights (which would be LED nowadays), and garage door openers are used. For any other loads, the tenants would have to negotiate the electric bill among themselves.
 
I don't think you can do that, Jeff, though I am struggling to find the relevant code article. My concern is that if one family moves out, and electricity is turned off to their unit until the next tenant moves in, the garage could be without power. Isn't there a code article that forbids supplying house loads from one tenant's panel?
 
charlie b said:
I don't think you can do that, Jeff, though I am struggling to find the relevant code article. My concern is that if one family moves out, and electricity is turned off to their unit until the next tenant moves in, the garage could be without power. Isn't there a code article that forbids supplying house loads from one tenant's panel?
Click to expand...

OK, never thought of that. The best solution would be to install a separate meter at the garage, with the bill to be paid by the property owner.
 
charlie b said:
I don't think you can do that, Jeff, though I am struggling to find the relevant code article. My concern is that if one family moves out, and electricity is turned off to their unit until the next tenant moves in, the garage could be without power. Isn't there a code article that forbids supplying house loads from one tenant's panel?
Click to expand...

You are looking for 210.25(A).
 
charlie b said:
I think I could successfully put forth a case for applying 225.30(B)(1). Neither homeowner has access to the other homeowner's service equipment, and neither service panel is in the common garage.
Click to expand...

I think your argument could be made successfully.
Depending on what code cycle the OP is on he may have issues in addition to Article 225.30 though. If he is on the 2017 he will need at least 2 circuits to each garage.
 
This is probably the exact reason why a house panel is required for common areas.... The garage imo, is a common area and needs to have it's own service. I would run this by the authority having jurisdiction and see what they will allow
 
How about building a fire wall between the 2 sides of the garage, making it (2) separate spaces and feeding each side with 1 circuit from the associated panel?

would that work?

JAP>
 
jap said:
How about building a fire wall between the 2 sides of the garage, making it (2) separate spaces and feeding each side with 1 circuit from the associated panel?

would that work?
Click to expand...

Aren't fire walls built before the rest of the structure? The fire wall has to completely separate the two sides, included trusses, and roofing material, doesn't it?
 
jap said:
How about building a fire wall between the 2 sides of the garage, making it (2) separate spaces and feeding each side with 1 circuit from the associated panel?

would that work?

JAP>
Click to expand...

Imo, that would work if the walls went up to the roof
 
jeff48356 said:
I would just run a 30-amp subfeed off one of the panels, then a small subpanel in the garage to feed the opener and lighting circuits. The cost of the electricity used is negligible, as long as only lights (which would be LED nowadays), and garage door openers are used. For any other loads, the tenants would have to negotiate the electric bill among themselves.
Click to expand...

A MWBC requires no grounding electrodes, once you install a panel, then you have grounding to do. A MWBC from each unit for the garage would be simple, each half has its own power
 
texie said:
You are looking for 210.25(A).
Click to expand...
I think looking for 210.25(B). (2014 NEC )

Now what if one occupant is the owner?? I know most here will not want to have to pay a minimum monthly charge of ~$20 for service - and on such a garage that monthly charge is probably more then the energy charge, possibly more then the energy charge for an entire year in some cases.
 
Just brain storming here, what if you took a 4 pole fused disconnect (4 poles so there is no risk in neutral current returning in the wrong panel), and placed it adjacent to the two services, since they are probably grouped. Then run a single branch circuit out of each to feed each pole in the disconnect. Add a neutral bar and create a MWBC as defined in article 100. You would have to choose opposite “phases” to comply. Since a single service drop exists I do not see a conflict with the joining of the neutral conductors since the disconnect separates them anyways. since they disconnect is fused, the MWBC doesn’t exist until in that closure so 210.4 A would be compliant as well. when you reach the garage place a non-fused 2pole disconnect which I believe still qualifies the system as a branch circuit but also complies with 225.31. Comments?


Sent from my iPhone using Tapatalk
 
giovanni0502 said:
Just brain storming here, what if you took a 4 pole fused disconnect (4 poles so there is no risk in neutral current returning in the wrong panel), and placed it adjacent to the two services, since they are probably grouped. Then run a single branch circuit out of each to feed each pole in the disconnect. Add a neutral bar and create a MWBC as defined in article 100. You would have to choose opposite “phases” to comply. Since a single service drop exists I do not see a conflict with the joining of the neutral conductors since the disconnect separates them anyways. since they disconnect is fused, the MWBC doesn’t exist until in that closure so 210.4 A would be compliant as well. when you reach the garage place a non-fused 2pole disconnect which I believe still qualifies the system as a branch circuit but also complies with 225.31. Comments?


Sent from my iPhone using Tapatalk
Click to expand...

If anything the front end of that arrangement can be in violation of 303(B), and you also would have improper paralleling of conductors (the supply side neutrals) would be in parallel to one another, but do not terminate at the same point on both ends, and in the 20 amp circuit situation also are two small to be installed as parallel conductors.
 
Status
Not open for further replies.
Top