Lessons learned from Self Install in Milpitas CA

[Nephi]

I want to give back to the forum that offered free advice. Thanks to all who contribute.

I'm done with the install (pretty much) and waiting for details to turn on the system.
And it is New Year's Day and a good to time to write down points that might help others.

System Specs:
Milpitas CA, PG&E
Roof - 4:12 or 18deg, 158deg azimuthal
Supplier/Distributor - Renvu.com

String inverter - 2 strings
15 total panels, Sunvia 325W, 72 cell panels 4.875kW system size, 7 and 8 panel strings
SMA Sunnyboy SB4000TL-US-22 with Speedwire Webconnect
Ironridge XR10 rails (no snow here!)
Soladeck passthru
External 3/4" EMT for all wiring from array to jBox, to inverter, to AC disconnect, to Main Panel
Cutler Hammer DG221URB AC Disconnect
pvlabels.com for compliant labels
CAT6 line from home router to inverter

New tools acquired: Long 1/4" drill bit, MC4 Crimp tool, Hex to square drive bits, replacement 16ft tape measure, RJ45 Crimp tool for network cable
Tools that would have made the job easier, but I was too cheap to purchase: Hole Drill for 1 1/4 roof penetration, Hole punch or step drill for 1 1/8 conduit connection to Soladeck, conduit bender

Total system cost (with permits and Home Depot runs) - $10776.39. Expected tax credit (30%) - $3232.92, for final cost of $7543.47
Expected payoff time - <5years

Status, as of today: Everything I have is now installed. See below. After finishing installation, will call for City inspection, and then for Utility permission to turn on.

Renvu.com experience. Very good. Their customer support is very good with personal attention to any and all questions asked. However, there were some things I learned.

1. Count panels when you receive them. Shipment of panels shorted me one. They shipped 14 by mistake. They are sending me a replacement next week.
2. Buy bare Cu from Big Box. I ordered the SLD (single line drawing) from Renvu for $250. After the design came back, it called for 6AWG equipment ground on the roof. But the default order was for 500ft of 8AWG cu. And I didn't need the 500ft min order from Renvu. Got 70ft from big box and saved money. Renvu sending me a full credit return for the misallocated order.
3. Don't order labels from Renvu. I ordered the default labels from Renvu. But if I had been paying attention, I shouldn't have. My city requires the red NEMA labels and not the Orange/white ANSI labels defaulted from Renvu. Ended up ordering custom labels (as required by the city) from pvlabels.com once the final numbers came back from the SLD. Pvlables.com placards come with stickers, so don't bother with rivets or rivet holes.
4. Aesthetics weren't an issue, so I went with the blemished Suniva panels. They look fine from 20ft away. No issues.
5. Default wire clips (Wiley ACC-PV) were difficult to use, and could only be installed to the thin frames of the panels. Not to the rails before panels are installed. OK, but splurging for rail mounted Ironridge clips might have saved some time.
6. Check quantities of Rail before final order. Ironridge length calculated is used by Renvu. Neither accounts for the ability to cut rails in half. I have 2 panels installed by themselves and the rail calculator didn't account for me being able to cut a long rail in 2.

Installation Notes:

1. Hardest part is finding the rafters. My roof has horizontal roofing boards under the plywood and over the rafters (from original shake roof?). No way to find the rafters from above without a $2500 stud finder. No thanks. I ended up trudging through the freshly insulated attic. Drilled up at one location, offset from a rafter, and then mapped upper locations across the roof from that base point. Then transferred those numbers to the top side roof. We hit every rafter where we could see the tails under the eaves. Not so exact at the roof hips where we couldn't see the tail ends for a good chaulk line.
2. Used lots of roofing gunk during install of flashing feet. Pushed in each drilled hole and rainbow shape on the bottoms of the flashings. Praying for a leak tight install.
3. Decided on Sunnyboy inverter partially because it includes the SPS outlet if the utility goes down and the sun is up. It's gimmicky, but could make the difference of keeping my freezer full of food if we ever get that Big one.
4. Lifting panels to the roof. Not a single person job! We built a simple trolley that runs on my aluminum ladder. I used a set of wheels from a skateboard and some scrap lumber. Pulled assembly up with a rope from above, and lifted from below. Tied it off at the top, and then my helper came up and helped lift it off the trolley at the top. Worked good enough to get them on the roof safely. Luckily I have 2 ladders for access to the roof while the panel is at the top!
5. Solar array connection to main panel - standard 2pole 30A CB should be installed opposite (on the far end from) the utility supply CB (200Amp in my case).

All in all, it has been a fun experience to date. Things aren't turned on yet, but I hope the inspection/power up experience will go smoothly. Thanks for all your help in giving me the confidence to make this happen. If you have any follow up questions, feel free to post here or PM me. I will share more details on request (cost sheet, calculations, SLD, etc)

[sdold]

Thanks for the report. I helped a friend with an install in Milpitas and found the city and fire people easy to work with, they even allowed variances from the setback rules. The inspector was pretty picky, especially with regard to the ground conductor. Good luck with the inspection and turn-up. It's a good feeling when it's all finished.

[schmoot]

Nice writeup. I'm also doing a self-install right now but in San Jose.

One question, is that I don't see grounding brushes on the EMT? I thought it was required to bond the EMT to ground?

[Nephi]

Yeah. I had an inspection and sure enough, the DC side requires grounding bushings on the EMT.


Actually there were several issues with my system that I'm stressing about getting fixed. I've got some other questions for anyone here:

Here are my list of issues from the inspector. With comments and questions:

1. Metal raceways containing grounding electrode conductor or circuits greater than 250 V require ground bushings and jumpers at all
conduit connectors
2. maximum 25 amp inter-connect circuit breaker for 20 amp rated AC output from inverter. 30 amp circuit breaker installed the date
3. provide unspliced grounding electrode conductor from roof mounted array to Building electrode system per 250.4 requirements and install
per 250.64
4. DC circuit conductors from roof mounted array identified with white insulation not approved for ungrounded system. conductors smaller
than #4 require insulation to be identified throughout its entire length and raceway system
5. conductors and receptacle powered when in standalone inverter mode requires overcurrent, ground fault, and short circuit protection
6. use of THWN – 2 rated insulated circuit conductors from roof mounted array to inverter unable to verify and required
7. provide torque specifications and torque wrench to verify module frame bonding to rails using WEEB type sole l bonding devices
8. loose PV conductor wire not secured under roof mounted array

1. bingo - see above.
2. Renvu's SLD took my 20Amp max output *1.25 = 25A, and spec'd a 30ACB. AHJ said no - use a 25ACB. Now I'm working on finding one. Not available at big box store.
3. Array ground goes to DC input. AHJ says that's not good enough. Violates 250.4. I'm trying to figure the best way to get the equipment ground from the roof to the house Ground rod. Right now my 8AWG THWN terminates at the DC connection. I need unspliced to the house.

Question - Do I Crimp/connect a 6AWG inside the DC connection box, run it outside the box, along the wall, and to the house ground Rod at the main panel?
See Grounding video on Mike Holt - minute 51.49 https://www.youtube.com/watch?v=mpgA...gIlIdVM7zJATHg u5hrrwn33Yh-R

4. My bad. pull the white THWN wires. Replace with Black (or Red, or whatever, but not White or Green)
5. This one bugs me. AHJ says I need a CB (OCPD) between the inverter and the SPS outlet. Even though I found this in the SMA documentation:

Section 690.10(B) of ANSI/NFPA 70, National Electrical Code® requires overcurrent protection for conductors “between the inverter output and the building or structure disconnecting means” in a stand-alone system. When installed and wired according to the installation manual, the SPS outlet conductors form a dedicated circuit that is isolated from other premises wiring of the building or structure. Power to the SPS outlet can only be supplied from the inverter and the inverter operates as a current limited device. Therefore, the conductors between the inverter and the SPS outlet should not require additional overcurrent protection.

See: http://files.sma.de/dl/18726/EPSCompl-US-TB-en-14W.pdf

Any other opinions out there? Not that it matters if the AHJ says I need it. Any easy ways to install a CB on a wall? what's the smallest box I can get a CB into?

6. Turns out Big box store doesn't supply THWN-2 rated. Only "-2" if it is greater than 8AWG. I have 10AWG. Only THWN rated. I need to pull all the DC wires out and replace with THWN-2.

Where is the best place to purchase THWN-2 10AWG wire?

7. I used Ironridge mid clamps for the panel grounding. The Suniva Installation instructions don't include that product in their UL testing. Only WEEB. I did hear from Ironridge and they provided a spec sheet that says they tested these particular Suniva modules with their grounding clamps and specified a torque value. That means I need to verify my torques on the roof to make sure they meet the 84inlbs called out in the additional information. If that doesn't work, I need to remove all the panels, then re-install with some other grounding. What a pain.
8. Clip loose wires up. I can do that.

[Amy@altE]

I'll give you an answer for #5. Get a Midnite Baby Box. For your AC breaker if the inspectior won't accept the manual's instructions.

[foo1bar]

Bell electrical supply gave me a good price when I called around looking for larger gauge THWN. But if you do call them to get a price, I'd place the order on the phone, and make sure you are charged per the quoted price BEFORE you sign a CC slip. (they overcharged me - I think they charged me the walk-up price instead of what they qouted on the phone.)
There's other electrical supply stores around the area as well. (I've bought from both Alltronics and Consolidated parts in Santa Clara)
One of those 3 likely will be able to supply the 25A breaker you need. (And there's also Bay Breakers in San Jose)

I'd point out that an OCPD doesn't *have* to be a circuit breaker - you *can* use a fuse. (of course it still needs an enclosure - so the Midnight Baby box Amy suggests might still be the smallest/cheapest option.)

I don't think the ground wire has to go all the way to the ground rod - probably not bad if it did though.
I think it can go to the ground block in your main panel and from there be connected to your ground rod/grounding system(s). (The ground block in the main panel can be used to join together GECs so doesn't have to be an irreversible connection there) That may or may not be easier for you to do.

[foo1bar]

Looking at the picture, I don't see any connection for the ground going to the metal on your roof. It looks like it's going to a little 3-wire connector, but that isn't connected to anything else. Maybe it is and I just don't see it in the picture. I'd review the grounding connection installation information for your inverter.

[emartin00]

For #3, you can splice a grounding conductor, as long as you use an irreversible connection (Crimp or exothermic). Just make sure you use a connector rated for grounding.
#5: If you present the information to the inspector, he should accept it. That is the whole point of putting that information in the manual. If he doesn't you can buy circuit breaker boxes that only have 2 slots.

[Nephi]

Thanks all -
MidNite's Babybox is interior rated. Mine's on an external wall. But nice suggestion.
Still looking for a easy fuse box or exterior breaker box.

Gnd rated irreversible crimp or braze. Much of what I find on line requires hydraulic crimp tool? Any recommendations on the crimp tool? Should I go from the roof conductor (6AWG solid) or from the end of the Green line (in the DC Disconnect (8AWG stranded) to the house ground rod? Seems like using the 8AWG Green stranded will violate the no splice rule? Not sure how that works since the EGC should terminate in the inverter and at the house Ground rod. Got to splice it somewhere.

[Nephi]

Not sure if this is OK, but I did find a Busmann screw in fuse holder that fits in a gang box. I'll wire this between the inverter and the GFCI plug. We'll see if the AHJ is OK with that.

It is rated to 15A, and has it's own switch for when you swap out the fuse (if ever). What do you think? 20160116_011144.jpg

[FNG AZ]

On #3. Sma 22 series does not have a GEC terminal so one is not required. The EGC can be spliced but using lay-in ground lugs to bond metal raceways and boxes is a lot easier and does not raise any crimping questions. DC EGC goes from array to dc disconnect bonding all metal boxes and conduit on its way. . A/C EGC goes from inverter to ground lug in panel. Bonding all metal boxes on its way.

For the SPS just pull it until the inspection is complete then install it per manufactures requirements.

http://ironridge.com/ig has the specs for the intergrated grounding

[schmoot]

Thanks for the update. Sorry to hear you had so many issues with your inspection, but it's definitely useful information to know what I can expect when I get an inspection.

I ran 8AWG wire for my install instead of 10AWG due to the issue in #4. Lowes and Homedepot only have THWN-2 in the 8AWG and ticker wires. This meant I needed to run 3/4" EMT instead of 1/2".

With regards to #8, were all of your wires loose and not supported? My install has a few loose wires, but most of them are zip tied to the racking. Wonder if I'm going to run into the same problems.

I'm really surprised by #3 as when I went to the building department in San Jose, they told me I just needed to bond the EGC to the main breaker's ground. This is also what I have seen other people do who have passed inspection. Maybe this is fall out from #1? Or that it was a grounded system due to the white wire? Or maybe I was just told bad information.

[Nephi]

Update from last Saturday:

I've completed some of the fixes. With help from some local electricians. I was looking for THWN-2 wire on a Saturday. Not easy since most Electrical supply houses are closed on Saturday. I called one, and the owner was on a job. He said he had some and come on by.

After arriving at his job site, I explained what I was looking for with ground crimps and he showed me the parts he had. Then he graciously lent me his crimp tool and supplied the parts at a very reasonable price. I couldn't have completed what I did today without him.

Roger Lin, Formosa Electric Corp, CA Lic #976353.

He had enough THWN-2 wire for me to get started. I pulled all the THWN load wire out between the jbox and DC Disconnect and replaced it with THWN-2. (It's blue, if you care)

I also installed the Bonding rings at the enclosure ends of the conduits (in the JBox and DC Disconnect) It was a tight fit. This is why chapman ratcheting tools were designed!

Lastly the equipment grounding. I acquired the crimping materials (Burndy YC6L12) from Roger above, but was worried if I had the right ones. I quick search showed me that the size wasn't exactly right. So I called another local electrician with very good results:

Jacky Wong,, CA Lic #961715

When I called, he said he could come by that evening. He was true to his word and stopped by. I explained what I was looking for and he gave me some free advice about what I could do with what I had. He also supplied some small spare parts from his truck that I could use. I really appreciated his kindness and service and would definitely recommend him to anyone looking for a local electrician.

I also received a torque wrench and confirmed the panel mount screws were tight to the 84inlbs (7ftlbs) spec.

For tomorrow, I've got to install the 25A CB and tie up as many of the loose wires I can reach. Also, I will probably add bonding to the AC side of the inverter, as a follow up email from the inspector leads me to believe that is what he is expecting:

Solutions seem ok

Ground bushings and jumpers throughout entire metal raceway system
Auxiliary electrode is permitted by electrical code option 2 is a common correction as long as bare #6 is protected

Hopefully the inspector will see the improvements and pass it off. Hoping for an inspection early next week!

[schmoot]

Good luck with the re-inspection. I don't think the blue wire is against code given that you are carrying ungrounded DC (white and green are the only special ones AFAIK), but when I was at the city of San Jose, they mentioned to be sure and use red and black wire, as some inspectors look for that.

[Nephi]

Update - The City inspector signed off! My solutions were accepted by him with visual inspection, etc. Signed Permit has been scanned and sent to Utility for approval. Very Exciting!

Since I had run the earth grounding electrode out of the DC Disconnect, against the wall, and to the house, the AC conduit didn't need bonding. But whatever, I did the rework, and now it's there. If the earth grounding electrode was in the conduit, it would have needed the bond, even if it is <250V. So be it.

Today I'm giving a casual presentation to an open group describing what I've learned installing my one PV. Should be fun!
Thanks again for everyone's input and ideas. I hope this "blog" has helped others make decisions.