Feeder entering then leaving garage, disconnect required?

[bjcouche]

Here's the scenario:
Detached garage with a subpanel in the garage, fed by a breaker in the main panel in the house. The wire run from the house to the garage is fed from a 100A breaker underground in conduit using 4/O, 4/O, 2/O, 2awg due to distance and voltage drop. The conduit enters through the garage floor at the wall nearest the house. At that location is a disconnect. Then the conduit continues on, back under the concrete floor, to the far garage wall where it emerges from the concrete floor to a load center. That load center is a MLO (Main Lug Only) panel.

The question: Does the MLO panel need to be changed to a breaker panel to act as a disconnect?
If the conduit between the disconnect and the MLO panel wasn't under the floor but instead routed around the inside perimeter of the building I'm sure that the installation would be fine as the disconnect would function as the disconnect means for the MLO panel. The problem is that the NEC considers conductors under concrete to be "outside" the building.

Brian

 

[ishiboo]

Here's the scenario:
Detached garage with a subpanel in the garage, fed by a breaker in the main panel in the house. The wire run from the house to the garage is fed from a 100A breaker underground in conduit using 4/O, 4/O, 2/O, 2awg due to distance and voltage drop. The conduit enters through the garage floor at the wall nearest the house. At that location is a disconnect. Then the conduit continues on, back under the concrete floor, to the far garage wall where it emerges from the concrete floor to a load center. That load center is a MLO (Main Lug Only) panel.

The question: Does the MLO panel need to be changed to a breaker panel to act as a disconnect?
If the conduit between the disconnect and the MLO panel wasn't under the floor but instead routed around the inside perimeter of the building I'm sure that the installation would be fine as the disconnect would function as the disconnect means for the MLO panel. The problem is that the NEC considers conductors under concrete to be "outside" the building.

Brian

I believe you only need a disconnect/main breaker if there are more than 6 circuits in the sub, even . Personally, given how cheap main breaker load centers are, that's all I would put in all but the smallest of garages.

 

[bjcouche]

I agree, actually the subpanel came with a breaker and I changed it over to a MLO panel. The problem is that I used 4/O, 4/O, 2/O, 2awg cable and the breaker won't accept anything larger than 2/O... I may have a solution for that though, I'll update when I verify it...

Brian

 

[Aceman]

The conduit enters through the garage floor at the wall nearest the house. At that location is a disconnect.

The question: Does the MLO panel need to be changed to a breaker panel to act as a disconnect?

You already have a disconnect for the garage IN THE GARAGE. You don't need two.

Why wasn't the underground conduit ran from the house straight to the garage panel?

 

[bjcouche]

Aceman, I agree that I shouldn't need two disconnect's, however I'm worried about the technicality that the NEC considers the run under the concrete floor to be _outside_ the building. Thus the feed leaves and reenters the building, and since it enters the building at the MLO panel, there would be a disconnect required at that location as well. Then there's the fact that the disconnect already in place is non fused but protected by the feeder breaker in the house.

The reasons for not taking the feed directly to the garage panel are now insignificant. I wish I'd done it that way now.

Brian

 

[sberry]

I don't think I would lose sleep over this, as long as there is a means at the garage to shut it down which there is.

 

[Aceman]

Aceman, I agree that I shouldn't need two disconnect's, however I'm worried about the technicality that the NEC considers the run under the concrete floor to be _outside_ the building. Thus the feed leaves and reenters the building, and since it enters the building at the MLO panel, there would be a disconnect required at that location as well. Then there's the fact that the disconnect already in place is non fused but protected by the feeder breaker in the house.

The reasons for not taking the feed directly to the garage panel are now insignificant. I wish I'd done it that way now.

Brian

I don't get it. I already told you that you didn't need two disconnects for the same building, but it almost seems like you want to install another one. Do it then, if you're so eager.

If you don't believe me, call your inspector. Doesn't matter to me either way though, it's not my money you're spending....

225.31 and 225.32 spell out the requirements.