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Where do you get "Where do you get "THWN-2 (90 °C) #12AWG conductor is rated for 30 A"? I'd say 20A. Also, do you need a PE to sign off on your roof load certification? I know at PE that did 2 of mine in NJ, Harry Braich, and he didn't charge an arm and a leg! -
Have you figured out how you're going to get the wires from the western roof section to the eastern roof section?Leave a comment:
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Have you mapped out the rafter relationship to the array that it'll actually be as you have it laid out in the image?
I didn't map mine out completely until after I had applied for the permit. (I figured out how many I'd likely need - but I didn't do exact placement until I was on the roof)Leave a comment:
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The filename you made an attachment has it misspelled in the filename.
AND at the bottom of the jpg it is misspelled.Leave a comment:
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Ok, Rafters @ 16", By providing enough support to all panels without exceeding the maximum spacing limits and observing Zone 2 and 3.
my best configuration:
rafter
1.......2......3......4......5......6......7...... 8
4-----2-----4-----2-----2----4-----2-----4
rail 1@ top: 1,3,6,8
rail2: 1,3,5,7
rail3: 2,4,6,8
rail4: 1,3,5,7
rail5: 2,4,6,8
rail6: 1,3,6,8
??? what do you think?Attached FilesLeave a comment:
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You need to fix the stuff like "IRRIVERSIBLE", too.Leave a comment:
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Instead of writing "1-17 MODULES", which indicates you'll have some unknown number of modules, I'd write "MODULES #10-18". As an engineer who has to make a lot of drawings, things like that bug me.Leave a comment:
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4th page is attachment points - but the rafters on there aren't 16" (or the panels aren't typical 1 meter wide)
I agree that not attaching them all to one set of rafters would be better.
But you don't want to exceed the maximum cantilever or maximum span from ironridge's documentation either.
BTW, if you do have access to the bottom of the roof (ie. can see where you drilled through when (not if) you miss the rafter, it'll make your life a lot easier.
FWIW, I'd probably go with even less cantilever at the corners where I think you're most likely to get more uplift from wind.
I think with 3 of 1m panels you'll span over 8 of 16" OC rafters. (probably 9 because you'll have extra length of rails that aren't covered by panels.)
I think in the writeup you have 4 attachment points for each rail, so you'll be doing every-other rafter, and 4' between them for one spot.
If it's 8 rafters, I'd try have the bottom rail be on rafters 1,3,5,7 the top rail on rafters 2,4,6,8 - distributes the load a little. more across the structure.
If it's 9 rafters, I might do 1,3,5,8 and 2,4,6,9.
I think you might even be able to do 3 points per rail - but I didn't do any calculations or run it thorugh ironridge's calculator, so you'd need to do that. (I think 5.5' apart would meet the ironridge recommendation. Or 4' apart with 1' cantilever on each side.) Adding a 4th is going to be more work - slightly more risk of leaks. But definitely will be stronger tie to the bldg.
I saw on the plans "irreversible splice" for the ground in the Jbox on the roof.
Is that necessary?
I don't know enphase installation requirements - so I'm asking the question.
The rafters are 16" spacing,Leave a comment:
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One line is confusing hard to tell what wires are in same conduit
From junction on roof to combiner panel should be 6 #10 and a # 6
( neutral and ground can be combined as neutral is communications only and ground is not a current carrying conductor.
The attachment plan 2nd page shows not nearly enough attachment points.
Also when laying them out don't attach all the rails to one set of rafters. Alternate attachments to spread load out as much as possible using all rafters below the array.
Looks like you are in wind zone 2 on sides and 3 lower corners. These areas will need more attachment points.
here is an update to 1 line diagram, i hope this will make more sense, watching Amy Schumer late at night and drawing is not funAttached FilesLeave a comment:
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I agree that not attaching them all to one set of rafters would be better.
But you don't want to exceed the maximum cantilever or maximum span from ironridge's documentation either.
BTW, if you do have access to the bottom of the roof (ie. can see where you drilled through when (not if) you miss the rafter, it'll make your life a lot easier.
FWIW, I'd probably go with even less cantilever at the corners where I think you're most likely to get more uplift from wind.
I think with 3 of 1m panels you'll span over 8 of 16" OC rafters. (probably 9 because you'll have extra length of rails that aren't covered by panels.)
I think in the writeup you have 4 attachment points for each rail, so you'll be doing every-other rafter, and 4' between them for one spot.
If it's 8 rafters, I'd try have the bottom rail be on rafters 1,3,5,7 the top rail on rafters 2,4,6,8 - distributes the load a little. more across the structure.
If it's 9 rafters, I might do 1,3,5,8 and 2,4,6,9.
I think you might even be able to do 3 points per rail - but I didn't do any calculations or run it thorugh ironridge's calculator, so you'd need to do that. (I think 5.5' apart would meet the ironridge recommendation. Or 4' apart with 1' cantilever on each side.) Adding a 4th is going to be more work - slightly more risk of leaks. But definitely will be stronger tie to the bldg.
I saw on the plans "irreversible splice" for the ground in the Jbox on the roof.
Is that necessary?
I don't know enphase installation requirements - so I'm asking the question.Leave a comment:
-
From junction on roof to combiner panel should be 6 #10 and a # 6
( neutral and ground can be combined as neutral is communications only and ground is not a current carrying conductor.
The attachment plan 2nd page shows not nearly enough attachment points.
Also when laying them out don't attach all the rails to one set of rafters. Alternate attachments to spread load out as much as possible using all rafters below the array.
Looks like you are in wind zone 2 on sides and 3 lower corners. These areas will need more attachment points.Leave a comment:
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