Back feeding small array through a Subpanel

[xbmasta]

Hello,

I'm designing a Solar PV System for a home located in Montgomery County, MD. There is a detached garage on the residence that the customer would like to place a small array (3 modules) on the roof of. The detached garage has a sub panel (GE TPL412C). Power is fed from the house to the sub panel via 8ga copper to a 30a THQL 2-pole breaker located in slots 1,2,3,4. There are 4 15a THQP 1-pole breakers located in slots 5,6,7,8 that feed circuits in the garage.

Now to my question. The 3 module array will produce roughly 4a, is it be possible to replace the 30a THQL 2-pole with a 30a THQP 2-pole, and add a 15a THQP 2-pole to back feed the solar production through? (As shown in the diagram below)

Thanks in advance!

 

[jaggedben]

It looks like you could do that, yes.

However, strictly speaking the 30A breaker is not necessary and is supposed to have a hold down. So I would just move the 8awg feeder to the main lugs and put the solar breaker in its place. You'll have 5 handles to disconnect the building, which is less than the maximum of 6 allowed.

I'm assuming the location otherwise complies with the requirements for the disconnect at the remote building.

 

[xbmasta]

Thanks for your response! Is the 8awg feeder large enough to be connected to the main lugs? I noticed on the wiring diagram on the back of the cover, it mentions 6 - 2/0 awg. I'm not sure if that is referring to the main lugs or not. However, I do see the chart for the slotted screw torque at the top right of the sticker that mentions it applies to line, neutral, and grnd terms and lists torque ratings for 2/0 - 14awg.

I believe the 30a breaker is serving as the disconnect at the remote building. We could install a disconnect outside the sub panel if we are able to use the main lugs to connect the 8awg feeder or I suppose we could upsize the wire to 6awg after the disconnect, however, at this point maybe it would be smarter to keep the 30a breaker as the disconnect?

Apologies for my incompetence, the electrician I would usually get advice from is currently on vacation. I'm learning..