NEC question

[willlgord]

I'm in the process of setting up an emergency power source for my house and I'm planning to build a small solar power system just for the lights and refrigerator (probably just a 2000 watt inerter with a 400 ah battery bank). The plan is to put the panels, batteries, charge controller and inverter in a detached garage and feed the house with it. Would this be against NEC? I know you cannot have more than one circuit feeding an outbuilding but what about the reverse? I don't want to back feed the garage service since I just want to feed three circuits in the house through a transfer switch. I may also provide a plug in for the generator in case I need it.
This is the transfer switch I want to use, only $99.99 from home Depot

 

[wyliesdiesels]

There is no simple way to do that.

U want utility power in the garage but also want to use the garage feeder to supply backup power to the house?

U need an interlock or transfer switch on the main service panel to cut utility power.

Problem is that wont allow utility power in the garage.

U will need a seperate feed for the backup supply.

 

[willlgord]

No, I do not want to use the garage feeder, I want to run a separate circuit in a separate underground conduit back to the transfer switch in the house for solar/emergency power. Is it legal?

The transfer switch would be installed next to the main panel to isolate the three circuits I want to power up from the grid.

 

[pattenp]

I don't see why not, as long as the transfer cuts out the main so no power from the solar can back feed to the service.

 

[wyliesdiesels]

No, I do not want to use the garage feeder, I want to run a separate circuit in a separate underground conduit back to the transfer switch in the house for solar/emergency power. Is it legal?

The transfer switch would be installed next to the main panel to isolate the three circuits I want to power up from the grid.

Aww ok. Then that would be fine. U didnt mention anything about a separate feed.

Move the 3 circuits to the transfer switch and connect generator to transfer switch via separate feeder.

 

[Sokoloff]

I think you can make the case that a 225.30(A) exemption applies, allowing you to have multiple feeds to the outbuilding. You would need a permanent sign/directory at each disconnect location showing other feeds and what they serve (225.37).

For grid-tie solar, I'd argue that the grid-tie is a feeder, even though the logical flow of electricity is in the other direction, the electrical danger is the same from someone who "cuts the power" to the garage and assumes that all the power lines are then dead. That's why 225.37 exists.

 

[willlgord]

Thanks for the reply, I just want to make sure everything I'm doing is up to code.