Self Installer in Carlsbad looking for guidance

[Dan Z]

I live in Carlsbad CA and I am planing a self-install of 20 panels (grid tied, micro-inverter, on flat tile roof). I am mechanical engineer and I have a fairly good idea of how to install the system, but I do have a series of questions on things like sewer vents, permitting, and wiring.

Is there anyone who is familiar with this region who would be willing to consult with me on these questions by email or by phone. I think it would take less than an hour or two total time (spread out over a week or two). I would be willing to pay for their time.

Thanks,
Dan

[sensij]

You can reach me at c7cc2f5e@opayq.com. If it is really just an hour or two, the time is free, and I'll be clear about what I can competently answer and what may require additional help.

[solar pete]

You can reach me at c7cc2f5e@opayq.com. If it is really just an hour or two, the time is free, and I'll be clear about what I can competently answer and what may require additional help.

mmm...dont feel very comfortable about this....I'll allow it, (for now, could change my mind any second), but not very happy, dont know why the guy cant list his questions for all the forum to see

[solarix]

You are a mechanical engineer right? Do mechanical things like heat? Carlsbad is a hot climate right? I would really encourage you to not put electronics on a roof in a hot climate. Yes I know, they guarantee them for 25 years and they will send you replacements, and you will be up there replacing them one at a time for years to come.

[sensij]

You are a mechanical engineer right? Do mechanical things like heat? Carlsbad is a hot climate right? I would really encourage you to not put electronics on a roof in a hot climate. Yes I know, they guarantee them for 25 years and they will send you replacements, and you will be up there replacing them one at a time for years to come.

In your rush to trash microinverters, I think you've misunderstood the OP's location. Carlsbad is just north of San Diego... according to Wunderground, in 2015 there were 1036 degree days of cooling, with a max of 24. Compare that to someplace like Philadelphia, with 1523 degree days of cooling (max of 22), or Phoenix, with 5066 degree days (max of 40), and the relatively temperate climate of the OP's location is clear.

[Dan Z]

Yes, Carlsbad CA is coastal climate (never too hot or cold - much different than my past homes in Austin and Cleveland).

OK first set questions (I have attached a my roof plan for reference - forgive my terrible hand writing). I think I have the answers to these questions already, but it never hurts to get confirmation.

1) I have three sewer stacks where I want to install the Panels. After some research, I decided the best plan is to cut them short, add elbows, and run them up the roof (under the panels) to a point higher than the top row of panels. Is this in fact the best plan (I would love to just cut them short and leave them under the panels, but I suspect this is not a good idea)? What is the best way to anchor the extended vents at the free end, which will be about 13" higher on the roof than the their penetration point?

2) For these elbows, I will need some clearance (about 6"). I would like to use the QuickHooks (side mount) with Iron Ridge 100XR (I think 10XR is too short to get me the 6"). Does anyone know form experience how much clearance there is between the rail bottom and the roof with this setup? If it is too low, I will need to use the QBase Standard (post style), which will yield more clearance (but is more costly and time consuming to install).

3) With 20 panels, I believe I need two branches. I was planing on having a branch of 14 and a branch of 6 to allow expandability on the shorter branch. Is this OK?

4) I have a cloths dryer vent that will be very close to one of the panels. Should I move (or heighten) this vent?

5) Can my dryer vent and extended sewer vents be located in the calfire 36" setback?

Tomorrow, I will post some questions on the electrical box (depending on what SDG&E tells me with regard to their RMA (Renewable Meter Adapter)). I have a center-fed 125 A box from Challenger.

[sensij]

1) I would say the best plan, if you have access, would be to do all the pipe rerouting in the attic. Unless you can get an elbow that matches your roof pitch exactly, you'll need a pair of them to get the arbitrary angle right, and then a pair on the other end to go vertical again. Doing it inside is just a 45 on each end, and you can secure it to the structure much more easily. In any case, don't just cut them short and cover them... if your inspector notices you won't get approved, and it probably isn't very good for the panels or for proper functioning of the vent.

2) Side mount quick hooks... so you have tile? Is it S-shaped or flat? With S-shaped, there is a chance you could mount the rail high enough on the hook to fit the pipe under in the valley of the S, but with flat tile, not so much. In any case, if you can, I think you would be better off re-routing the pipe under the roof, not above it. Makes this problem go away.

3) Are you using either Enphase M215's or M250's? In either case, a branch of 14 and one of 6 is fine. If you are using Enphase trunk cable, you'll either need a fused combiner or to run each string into its own circuit breaker in the panel.

4) Move it if you can. You don't really want the lint and moisture coming out that vent anywhere near your panels.

5) No regulations I know of prevent the vents in the PV setback area.

With respect to tomorrow's questions, about a year ago another forum member was in a similar situation, with the same electrical panel:
https://www.solarpaneltalk.com/forum...r-fed-and-100a

The RMA was still vaporware at that time, and it looks like that member ended up replacing the panel during the install. Since your array is small enough to be connected through a 25 A breaker (somewhat limiting expansion potential), if you can drop your main supply breaker down to 100 A, you should be able to get away with the panel you have.

[foo1bar]

I decided the best plan is to cut them short, add elbows, and run them up the roof (under the panels)

I second the idea to do that inside the attic.
It looks like you're planning to run the panels in portrait, with the rails running horizontal?
If so, you need enough clearance under the rail for the pipes because the pipe-on-top-of-roof option you're sugesting would be perpendicular to the rails. So 10XR vs. 100XR doesnt' matter.


3) With 20 panels, I believe I need two branches. I was planing on having a branch of 14 and a branch of 6 to allow expandability on the shorter branch. Is this OK?

4) I have a cloths dryer vent that will be very close to one of the panels. Should I move (or heighten) this vent?

Is it north of the panels?

re-routing would be good, but IMO isn't strictly required. lint dust will mean lower production - heat/moisture I wouldn't be too concerned about if it's only close to the panel, not under it.

I would add an indicator of North on your roofplan.

You'll also need to determine rafter location and (approximate) rail location.

Is it a tile roof? (I wouldn't want to deal with walking around on a clay tile roof) I'm not familiar with QuickHooks - but I only really looked at mounts for composite roof.

[Dan Z]

Flat tile roof (details are in the original post).

The vents are close to the eves, so very tight to get at them in the attic. I can crawl in there again and re-assess, but it was definitely very tight with almost no room to maneuver. If roof routing is acceptable it would probably be easier. I can get elbows at 22 1/2 deg (a close match to my 4 in 12 roof pitch at 19.5 deg).

Using M250 with Solarworld Plus 285 Mono.

Will move dryer vent to other side of roof.

Portrait panels. Horizontal rails with mounts 6' spaced. You are correct on the 10XR vs 100XR for the pipe. I will need about 2.5" under the rails for the straight run. But for the elbows, the clearance will be to the underside of the panel and I need about 6", so rail height will matter. I think I will just have to buy parts and mock it up.

Still waiting on SDG&E reply on the RMA.

One question: My lowest panels are almost at the roof edge (2 story house). So, I cannot walk along the the roof to install the lower mid-clamps. Can I reach along the 40" width of the panels to tighten them? It seems like a long reach for my arms (I'm about 5' 9"). I would hate to have to tighten them atop a 30 ft ladder leaning on the gutter.

[foo1bar]

Portrait panels. Horizontal rails with mounts 6' spaced.

6' spacing would have been nice for me - I had to do 4' because with 4' spacing the city didn't require any additional engineering/load analysis.

You are correct on the 10XR vs 100XR for the pipe. I will need about 2.5" under the rails for the straight run.

Plan on more than that.
OD of 2" PVC is 2.375" Then there's the rim of the fittings which will lift it up off the roof by at least 1/8"
And you need to measure 2.5" between the rails and the edges of the tile that are farthest from the rafter. if you look at it as the roof profile being like a sawblade, your pipe is resting on the tips of the teeth - so you need room for the pipe between those tips and the rail.

Also - 22.5 vs. 19.5;
tan(3 degrees) * 69" = 3.6 inches

But for the elbows, the clearance will be to the underside of the panel and I need about 6",

If you're 6" above the roofline, and the angle is steeper than the roof angle (22.5 vs. 19.5), you're going to need *more* clearance under the rails as you get further out.


Are you thinking that you'll come up 6" to have space for the flashing, then have a lower slope than the roof so your pipe gets closer to the roof as it goes towards the peak?

The vents are close to the eves, so very tight to get at them in the attic.

If it's too tight inside the attic, fix it from above or below. Either tear up some drywall or make a hole in the roof to get access from above.
(I know you're thinking it's easy for me to say - I don't have to do it - but IMO it's the right way to do it.)

Can I reach along the 40" width of the panels to tighten them? It seems like a long reach for my arms (I'm about 5' 9"). I would hate to have to tighten them atop a 30 ft ladder leaning on the gutter.

I'm a little taller, but I reached across. It's a 2-man operation - one holding the panel in place while the other tightens.

[sensij]

Also - 22.5 vs. 19.5;
tan(3 degrees) * 69" = 3.6 inches

4:12 roof pitch is more like 18.5 deg. Over 10 ft of roof travel (hypotenuse), that is around 7" of rise. The pipe should flex to soak some of that up, but, yuck.

[foo1bar]

4:12 roof pitch is more like 18.5 deg.

You're right - it's 18.43 deg.

Over 10 ft of roof travel (hypotenuse)

I used 69" since that's the height of one panel. But 10' certainly is plausible - going two panel heights.

I think the OP can plug their own guesstimates for angle/distance into the equation and reach their own conclusion.

[Dan Z]

Flex of the pipe will take care of the theoretical trigonometry issue. Yes, the saw tooth shape is why I won't know if it fits unless I mock it up. Tearing up roof crossed my mind. Still hoping to avoid this. Probably, I would just drop to 18 panels as a worst case.

I'll double check with the city (or someone who knows the area) on the 6' spacing. I think Iron Ridge has all the engineering calcs ready to present if needed.

FYI there is a whole different thread on the breaker panel. Subject: Electrical Panel & Solar - Center Fed and 100A? Not sure how to link to this.

https://www.solarpaneltalk.com/node/307069

Ignore the link below.
To add a link use formatting button with the image of a link of chain on it.
Any other "Add Link" method does not seem to work right.