DIY installer with some questions on my plans

[dmrlook]

Hey All - first time on this forum - looks like a lot of great advice here. I've got a few questions as I start on my solar system journey. I am planning a DIY solar system for my home. My south facing roof has enough space for 13 panels (I could perhaps get one more if I move to landscape orientation, but the extra work/cost is not worth the extra panel).

I am planning on using the LG 375w panels and pairing those with Enphase IQ7+ micro-inverters. Enphase website says this will work. My first question is, does this seem acceptable. I am purposely going with a more expensive panel to max my production given my limited south facing roof space.

The attached image shows my planned layout. You can see how I plan to wire things together (different wires are color coded). The 5 top panels will be connected (in parallel) using the enphase Q-Cable (purple in image). I then plan to route the end of that cable into a j-box, convert to outdoor rated 12 awg wire, and send to a j-box on the second row where I convert back to Q-cable (j-boxes and 12 awg wire shown in red). The 12 awg run will be enclosed in conduit.
Question 2: Any concerns with this?

My understanding is I need to use metal conduit.
Question 3: Am I correct, or can I use the PVC stuff?

The one single panel on the bottom left is working around some roof vents. Note the bottom row of panels is close enough that I believe i can run the Q-cable directly into the Solodeck box (shown in blue). Within this box, I'll combine both Q-Cables in parallel with 12 awg wire which will enter my attic and make it's way to the other side of the house where I'll have the AC disconnect, production meter, and then into my main panel (20 amp 2 pole breaker). All of this will be permitted and inspected per state/local codes.
Question 4: Any concerns with this plan of action?

I plan to use 12 awg 2 wire romex through the attic.
Question 5: I am assuming I do NOT need conduite for this run as it is inside the home. Is this correct?

The green wire is my ground, which will be connected to the mounting system (I am going with the Iron Ridge system, and will connect the ground as per their instructions). I have not calculated the guage yet, but am assuming it will be in the 6-8 awg range (bare copper). I'll need to confirm when I pull the electrical permits. The 2 grounds will combine to the grounding bar in the solodeck, and then continue one as a single ground wire throug the attic to the other side of the house where the ground is.
Question 6: Does anyone know how this ground wire can be run - does it need to be in conduit, or can I run it as is through the attic?

That's it for now. Hopefully I've brought this thread to the correct spot.

Thanks all for the help!
RobUntitled.png

[J.P.M.]

If you haven't already done so, I'd tap the brakes and see what local building codes and regulations, and also what fire regulations might require. There is usually more to getting a residential PV system permitted than an electrical permit.

A quick look at your sketch makes me wonder that the roof setbacks you appear too have settled on may be a bit short.

BTW, what's your annual usage and how much of that would you like to offset with PV ?
Also, have you done any modeling to get a SWAG on annual output from a 4.5 STC kW system might be ?

[dmrlook]

If you haven't already done so, I'd tap the brakes and see what local building codes and regulations, and also what fire regulations might require. There is usually more to getting a residential PV system permitted than an electrical permit.

A quick look at your sketch makes me wonder that the roof setbacks you appear too have settled on may be a bit short.

BTW, what's your annual usage and how much of that would you like to offset with PV ?
Also, have you done any modeling to get a SWAG on annual output from a 4.5 STC kW system might be ?

Thanks for the reply - I'm way ahead of you. I am already in contact with my local building inspector and am aware of the setbacks, roof load requirements, etc. My setback from the ridge is the required 3 foot. On the other 2 sides, since I have the other roof lines, I am all set with what I need.

My monthly usage 650 kWh. My offset is as much as I can fit given the roof I have at 375*13=4875w. I do expect payoff in about 7 years.

Thanks,
Rob

[foo1bar]

I am already in contact with my local building inspector and am aware of the setbacks, roof load requirements, etc. My setback from the ridge is the required 3 foot.

They (AHJ and fire dept) may allow even less setback since you have the N side of the ridge readily accessible. They may want confirmation that the attic underneath is contiguous space between the north and south areas - for venting reasons in case of a fire.

My understanding is I need to use metal conduit.
Question 3: Am I correct, or can I use the PVC stuff?

PVC isn't very good for roofs - it's hot up there and exposed to UV light.
I don't think there's any real requirements that say you can't use PVC - BUT I think everyone uses EMT, so I think you should too.
If you can support the Q cable well enough from one row to the other, I think you can just stay with Q cable for the whole run - will require a few connector spots being "plugged".
At least when I looked at enphase for my DIY install, that was a possibility.

The one single panel on the bottom left is working around some roof vents. Note the bottom row of panels is close enough that I believe i can run the Q-cable directly into the Solodeck box (shown in blue). Within this box, I'll combine both Q-Cables in parallel with 12 awg wire which will enter my attic and make it's way to the other side of the house where I'll have the AC disconnect, production meter, and then into my main panel (20 amp 2 pole breaker). All of this will be permitted and inspected per state/local codes.
Question 4: Any concerns with this plan of action?

I'd probably have 3 Q cables in that spot - one for the top row, one for the left panel and one for the right bottom row.

I plan to use 12 awg 2 wire romex through the attic.
Question 5: I am assuming I do NOT need conduite for this run as it is inside the home. Is this correct?

I believe Enphase says you don't. That it's same as any other 20A branch circuit.
I'd draw/specify it that way on my plans and if the AHJ doesn't object, I would use regular NM-B (romex) inside)

[dmrlook]

They (AHJ and fire dept) may allow even less setback since you have the N side of the ridge readily accessible. They may want confirmation that the attic underneath is contiguous space between the north and south areas - for venting reasons in case of a fire.

Good point -however what you don't see in the drawing is I have 3 roof vents up there in that 3 foot of setback, so even if I could move up a little, it does not buy me any more space for additional panels, so sticking with 3 foot is convenient. And the attic under the north and south faces is contiguous.

PVC isn't very good for roofs - it's hot up there and exposed to UV light.

Good point - I'll stick with the EMT as you suggest. Thanks.

If you can support the Q cable well enough from one row to the other, I think you can just stay with Q cable for the whole run - will require a few connector spots being "plugged".
At least when I looked at enphase for my DIY install, that was a possibility.

I'd probably have 3 Q cables in that spot - one for the top row, one for the left panel and one for the right bottom row.

Yeah - I was worried about the support of the Q-Cable which is why I went with j-boxes/conduit. However your suggestion makes me realize that I can minimize voltage loss by coming off of the left side of that top row and going directly into the solodeck, and combining all 3 panel sets in parallel in there. Thanks!

I believe Enphase says you don't. That it's same as any other 20A branch circuit.
I'd draw/specify it that way on my plans and if the AHJ doesn't object, I would use regular NM-B (romex) inside)

Yes - that was my plan 20 awg NM-B romex. Which bring me to another question. Is inside the solodeck considered "inside" or do I need to use an outdoor rated wire like a type UF cable from inside the solodeck into a j-box in my attach and then transition to NM-B?

Thanks again!
Rob

[foo1bar]

Yes - that was my plan 20 awg NM-B romex. Which bring me to another question. Is inside the soladeck considered "inside" or do I need to use an outdoor rated wire like a type UF cable from inside the solodeck into a j-box in my attach and then transition to NM-B?

I think the soladeck is considered outside - so a "wet" area.
But I don't like the idea of doing a 2nd transition just inside the roof inside a jbox in the attic just to switch from THHW to NM-B.
I'm not an electrician, so I do not know what is "typical" installation best practice for this type of situation - nor what the AHJ will be OK with.

[dmrlook]

I think the soladeck is considered outside - so a "wet" area.
But I don't like the idea of doing a 2nd transition just inside the roof inside a jbox in the attic just to switch from THHW to NM-B.
I'm not an electrician, so I do not know what is "typical" installation best practice for this type of situation - nor what the AHJ will be OK with.

I'll talk to the AHJ about this and go with whatever he wants since that will maximize my chances of approval.

Thanks!
Rob

[foo1bar]

I'll talk to the AHJ about this and go with whatever he wants since that will maximize my chances of approval.

They probably will say "I can't give advice" if you ask for advice.

So you probably want to go with "I'm planning to do X, Y, and Z. Do you see any code issues with me doing that?"