Need advice on drawings

[GreenTeeCrazy]

Code is always subject to interpretation and the only thing that matters at this point is what will get you past inspection. Enphase's position is you don't need that #6 grounding conductor at all because all the grounding required for an ungrounded PV system is provided by the grounding conductor in the Engage cable (assuming you use a suitable washer to bond the M250 to the rail). Some inspectors don't agree.

Correct about the M250
#6 is for the rails and the Solar modules ground.
is it ok to have the ground wire be installed as a "n" shape? start from 1st rail go up to the 6th rail then connect back at the 1st rail again?

[tehan]

Enphase M250 are grounded using engage cable.
So i guess it ok to run the cable from point A, run it around the circuit and return back to point A?

Code is always subject to interpretation and the only thing that matters at this point is what will get you past inspection. Enphase's position is you don't need that #6 grounding conductor at all because all the grounding required for an ungrounded PV system is provided by the grounding conductor in the Engage cable (assuming you use a suitable washer to bond the M250 to the rail). Some inspectors don't agree.

[GreenTeeCrazy]

I like these Enphase brackets, but for some reason you have to elongate the holes to fit a standard square box. Also, the M250s have integral ground that carries through to the racking if properly bonded by the racking manufacturer's instructions. There should be no additional ground wires required. See http://www.ecodirect.com/ProductDeta...FYQ_aQodaE0IbA

THAT'S IT!!!!

Exactly what i am looking for.

[JFinch57]

Connecting the Aluminum J-BOX to the Al rail:

Any adapter or plate should i use or can i use a zinc plated self-tapping screws from inside J-Box to the rail?

Running the #6 ground wire:

As you can see in my diagram, I run the ground wire from top to bottom in circuit 2, then run it to Circuit 1 going up to the top rail then back to the J-Box by the lower left end. in the shape of "nj"

Is it ok by code to backloop the ground wire?

I like these Enphase brackets, but for some reason you have to elongate the holes to fit a standard square box. Also, the M250s have integral ground that carries through to the racking if properly bonded by the racking manufacturer's instructions. There should be no additional ground wires required. See http://www.ecodirect.com/ProductDeta...FYQ_aQodaE0IbA

[GreenTeeCrazy]

All i could find at HD was the Aluminum 1 and 2 gang box
NEC 2011.
Enphase M250 are grounded using engage cable.
So i guess it ok to run the cable from point A, run it around the circuit and return back to point A?

My installation setup:

Connect Engage cable to J-Box 2 in Circuit 2 using liquid tight adapter.
From J-Box 2, run #10 inside Ultratite conduit connect to J-Box 2 using 1" liquidtight adapter.
using large stapler to hook the conduit to the 3ft siding (valley), If the bend is too great then i'll have to use 1 of those 90 degree adapter.
Tie the conduit to the rail using Stainless steel or nylon zipties to keep the conduit from touching the roof every 3 feet. no more than a ft away from J-Boxes

and do the same again on Circuit 1 to the AC Combiner.

The whole wiring is done outside the house.

[foo1bar]

I
running the cable from Ciruit 2 to Circuit 1 to MNPV6 using 1" Utlratite NM conduit. After inspection is passed ( permit 1st lol) I am going to spray paint it to match the siding of the house. I'll discuss that with the inspector 1st.

How are you supporting it as it goes across the roof, then up the wall. (You won't want it on on the roof - you probably want it 4" off the roof because of temp de-rating)
How are you getting it around the edge of the roof at the top of the wall?

Are you completely exterior to the structure with all your wiring? (If you were doing a regular string inverter, you'd need the wires inside the structure inside metallic conduit I think... With enphase microinverters, I'm not sure how those rules apply to them) But I think you're completely outside - so that shouldn't be a problem.

With flexible conduit you will need to make sure that you're not making too many bends because of it sagging between support points.

[Naptown]

All hardware should be stainless steel
What NEC code cycle are you on?
You may be able to just ground each rail and bond the inverters to the rail with web clips. Same with modules.
Most racking now a days allows this.

[GreenTeeCrazy]

Connecting the Aluminum J-BOX to the Al rail:

Any adapter or plate should i use or can i use a zinc plated self-tapping screws from inside J-Box to the rail?

Running the #6 ground wire:

As you can see in my diagram, I run the ground wire from top to bottom in circuit 2, then run it to Circuit 1 going up to the top rail then back to the J-Box by the lower left end. in the shape of "nj"

Is it ok by code to backloop the ground wire?

[sdold]

Irreversible is/was removed

I just meant that you need to check your spelling, you had two wrong letters in there. Clean this stuff up or they'll think you are working for Substandard Construction. heh heh

[sensij]

2011 NEC Table 310.15 (b)(16)

[JFinch57]

The way in which the ampacity adjustments and corrections was done is sort of logically backwards... the conductor rating should be adjusted down and checked against the rated ampacity of the circuit, not the circuit ampacity adjusted up. 12 AWG is OK for the 9 panel strings.

90 deg 12 AWG base ampacity = 30 A
adjustment for conduit fill = 30 * 0.8 = 24 A
correction for temperature = 24 * 0.71 = 17 A

17 A > circuit rating of 11.25 A - OK
17 A > 15 A breaker - OK
25 A terminal rating for 12 AWG > circuit rating of 11.25 A - OK
15 A breaker <= 20 A for 12 AWG - OK

What chart are you using for 12 AWG? This says 20A. http://www.cerrowire.com/ampacity-charts

[GreenTeeCrazy]

Here are the .doc files for the proposal work:

Roof pemmit

[GreenTeeCrazy]

The way in which the ampacity adjustments and corrections was done is sort of logically backwards... the conductor rating should be adjusted down and checked against the rated ampacity of the circuit, not the circuit ampacity adjusted up. 12 AWG is OK for the 9 panel strings.

90 deg 12 AWG base ampacity = 30 A
adjustment for conduit fill = 30 * 0.8 = 24 A
correction for temperature = 24 * 0.71 = 17 A

17 A > circuit rating of 11.25 A - OK
17 A > 15 A breaker - OK
25 A terminal rating for 12 AWG > circuit rating of 11.25 A - OK
15 A breaker <= 20 A for 12 AWG - OK

I agree with you, I am trying to get the lowest drop/rise %

[GreenTeeCrazy]

I would like to thank everyone who for taking their time to answer and guide me in my quest.

Irreversible is/was removed

If you mean the Enphase engage cable, I am running it as "5" shape. from top right panel to the the lower bottom left next JBOX on both circuits.

running the cable from Ciruit 2 to Circuit 1 to MNPV6 using 1" Utlratite NM conduit. After inspection is passed ( permit 1st lol) I am going to spray paint it to match the siding of the house. I'll discuss that with the inspector 1st.

Also i do have to access to the attic, so i installed over the weekend a blocking system to support more weight on my aging roof, In the worst case scenario that if i missed a rafter, i can always install 2x6 joint under the roof membrane .

@JFinch57, About the PE, I am going to wait and see if the inspector request the report, But thank you for the info. Did you do your own installation?

[sensij]

The way in which the ampacity adjustments and corrections was done is sort of logically backwards... the conductor rating should be adjusted down and checked against the rated ampacity of the circuit, not the circuit ampacity adjusted up. 12 AWG is OK for the 9 panel strings.

90 deg 12 AWG base ampacity = 30 A
adjustment for conduit fill = 30 * 0.8 = 24 A
correction for temperature = 24 * 0.71 = 17 A

17 A > circuit rating of 11.25 A - OK
17 A > 15 A breaker - OK
25 A terminal rating for 12 AWG > circuit rating of 11.25 A - OK
15 A breaker <= 20 A for 12 AWG - OK