Enphase Project

[Mark]

I am wrapping up my solar install.  I have 16 M215 enphase with factory truck cable, 16 SolarWorld 250watt panels and SnapNRack mounting system.  The enphase cable is center fed with 8 to either side of the jbox.  I have all mounted on my south face of barn with room, already mapped for expansion, for additional 8.  My question comes in at the PV A/C combiner box.  The NEC allows for 120% of the main, which in my case is a 200 amp, allowing my a total of 40 amps backfed.  Washington State has production based incentives that pay on gross production in addition to net meter benifits.  I was therefore wanting to use a metered panel with a 100 amp bus, 40 amp main and 2 20 amp OCPD.  Tie it into the main panel with a 40 amp OCPD.  Would this second panel be considered a subpanel or   Being the bus cant go over 80 amp it would be equal to/ less than bus rating.  I've read nec 690.64(b)(2) and nec 705.12(d) and think that I'm good at this.  Any advise would be appreciated.  As soon as I get permit I will post the link to the enlighten so all of you can see my system production.

Mark

[LowGear]

Hi Mark,

To quote my electrical inspector:  "We've ascertained that you are NOT a licensed electrician."  The guy had no sense of humor!  By the forth inspection he had challenged mine as well.

16 X 210 = 3360 Watts.  3360 / 120 = 28 Amps.  I'm confused.

If I were shooting for Washington States wonderful gross production rebate of 50 cents a kilowatt I'd have my supplier or a certified designer in on the project.  Don't the enphases disqualify you for this rebate?  And isn't SolarWorld in Oregon?

Ah, to be back in Washington where home owners can actually pull their own electrical and plumbing permits.  Dream on Kona Boy.

I have a very similar array but choose the SunnyBoy 6000US inverter instead.  I allowed my pocket book to make the decision.  What was your criteria.

Casey

[Mark]

Casey

The 120% ruling is I can go over my main breaker by 20% so, 120% of a 200 amp service would allow for 40 amps of backfed power.  NEC's math 120%x200amp-200amp=40amp
The Solar World ingots are from Vancouver Washington.  I will not get the full $.54 without panel and inverter from Washington but will qualify for about $.35.  Even with all coming from out of state we get $.15 yet pay $.06 KWh
I've had bad luck with string inverters here in Tacoma and decided to use micro inverters, cost also a consideration.  The system all said and done should be at about $7000. plus alot of extras to try and sell.  I already have enough inverters and cable for my next string.  Panels are the only thing that I'll need unless I run my smaller panels I have but then I would go with a D380 "twin pack".
The new m215 are rated at 215 watts, I'm not using the m210
Has anyone used a dc-dc power optimizer like Solar Edge.  I might consider it with a string inverter?

Mark

[LowGear]

Hi Mark,

Eastern Washington huh.  6 cents a KWH is so wonderful. 

Do you get any rebates or credits besides your 30% federal tax credit?

Do you understand why NEC allows 200 Amps in and only 40 Amps out?  I paid to have my system designed as that is the only option in Hawaii.  I also paid $1000 to just get the permit pulled. 

The good news is that at 44 cents a KWH I'm saving $100+ a month with my 15 SW245s.  And we got another 35% from the state income tax credit department.

Casey

[Mark]

Hi Casey,

I met with my power company today and feel good about the process moving forward.  I also spent half the day at the permitting office trying to get a clarification of the "gray area" with a sub panel.  I fully understand both the NEC regulations and the reason for a 40 amp limit on my main panel.  Theoretically I will have 240 amps on my bus bar as that is the sum of all input.  Factually, I will never have on every circuit in my house at the same time to max out my panel and have not had the main breaker trip.  My system is 240 volt and allows me a total of 32 amps of actual input back through meter, I have to allow for oversize of the OCPD.  I designed the system myself and want room for expansion.  I have 4000 watts of panels, this is the number the power company is using.  The permit department is using the inverter output numbers.  So what have I learned today?  I need to wire in the system how I feel best, call for an inspection, have the inspector tell me to rip it out and what he wants, then do the job and get the permit signed off.  I think this is the way it is done if I correctly understood everyone today.  If this is standard electrical practices, I thank God I'm a truck mechanic.  With that all said, I'm still happy I'm this far as I've had a partially completed job done for over a month and the neighbors are starting to ask ?..  I at least have a path to completion, allbeitt a little obscure to the onlooker, it seems to be the official procedure...  My electric permit ran me $90. and then $70. for each time I get a different inspector telling me to rip it out.  Worst case, their are three for this area, so maybe $400. before I get the same inspector, who might even change his mind when he sees what he required in place.

Tax credit, I will get a cash grant for 30% as a federal check.  My accountant is working on it.  I went in with two other shops on the parts bought , we purchased from a state overstock auction.  I ended up with alot of pieces I dont need but after selling them I should have a system almost paid for.  The cash grant is the tricky part as the value has yet to be agreed upon between the 3 of us.  We are all looking at the cash grant  One of the buyers is considering using his on an off grid cabin and if he does I will get half of the grant from the purchased items even though I only got the inverters and cable.

Mark