Solar install turning out really bad - looking for some help/advice please.

[HX_Guy]

I just thought about that 1" conduit from your combiner box to the attic. Will it be big enough to even run 2 x #2 AWG + ground + that red wire for your panel string?

If not, you need to change your plans concerning that #2 wire and reduce it to what is really needed. The #6 might work if it meets the voltage drop calculation.

According to the conduit fill calculator I used, it comes out to 31% conduit fill, which I believe is fine per NEC. Plus it's what the permit says.

[SunEagle]

Edit: Please do not clip the strands to make it fit in the undersized terminal block. Please.

I agree with you. NEVER clip any strands to make a wire fit into a terminal.

[SunEagle]

Definitely do not need #2, that's way overkill (good for 115A @ 75º C). The inverter will never "request" more than 34.5A per SolarEdge, even with the NEC 125% rule, that's 43.13A. 6AWG wire is good to 65A @ 75ºC.

I just thought about that 1" conduit from your combiner box to the attic. Will it be big enough to even run 2 x #2 AWG + ground + that red wire for your panel string?

If not, you need to change your plans concerning that #2 wire and reduce it to what is really needed. The #6 might work if it meets the voltage drop calculation.

[HX_Guy]

IMO filing a plan change is easier.

Is there any reason that #6 isn't OK? (ie. do you really need #2 or anything larger than #6? If not, fix the plans to be what they should have been in the first place.)

Definitely do not need #2, that's way overkill (good for 115A @ 75º C). The inverter will never "request" more than 34.5A per SolarEdge, even with the NEC 125% rule, that's 43.13A. 6AWG wire is good to 65A @ 75ºC.

[foo1bar]

Yeah, probalby not the way I'd want to go. Easier to just get a couple new terminal blocks and replace the existing ones. I just need to see if I can remove those little DC+ and DC- plastic pieces and attach to the new terminal blocks so it looks "oem".

IMO filing a plan change is easier.

Is there any reason that #6 isn't OK? (ie. do you really need #2 or anything larger than #6? If not, fix the plans to be what they should have been in the first place.)

[HX_Guy]

Not a new permit - a change to the existing permit.
Probably for this one you can make the new plan, probably they'll want the changes in red (easily identified when reviewing).
And I'd probably put a note like:
"Change: Changing wire size from #2 to #6 for wire from inverter to main panel. Was mistake on original plans."

For a small change like that, possibly they won't even charge you.
(depends on the planning dept.)

Obviously you need to make sure that #6 is OK code-wise. I don't recall what exactly your setup is. If it's OK for amperage with whatever de-rating is appropriate for it's location, then that's the route I'd take.


Obviously asking the planning dept what they want in a plan-change submission and how much they charge should just take a quick phone call. (probably 30 min on hold and a 3 minute conversation)

I asked the inspector and she specially said we would need a new plan submitted. I think too many changes for just a revision (new conduit fill calculation etc). Ill give them a call too though.

[foo1bar]

Well, it looks like we kind of have to do new permits. I called up SolarEdge and the inverter will not accept anything bigger than 6AWG wire. An adapter would need to be used, which isn't shown on the permit, so that wouldn't pass either.

Not a new permit - a change to the existing permit.
Probably for this one you can make the new plan, probably they'll want the changes in red (easily identified when reviewing).
And I'd probably put a note like:
"Change: Changing wire size from #2 to #6 for wire from inverter to main panel. Was mistake on original plans."

For a small change like that, possibly they won't even charge you.
(depends on the planning dept.)

Obviously you need to make sure that #6 is OK code-wise. I don't recall what exactly your setup is. If it's OK for amperage with whatever de-rating is appropriate for it's location, then that's the route I'd take.


Obviously asking the planning dept what they want in a plan-change submission and how much they charge should just take a quick phone call. (probably 30 min on hold and a 3 minute conversation)

[HX_Guy]

As I noted, it is not compliant with the NEC. And if done improperly it can make the connection more likely to overheat or make the remaining strands more likely to break.
As long as there is strain relief on the wire to prevent it from being pulled on at the terminal, I would consider it safe, but of course I could not encourage it.
Be very careful not to scratch, nick or repeatedly bend the remaining strands, since that would make them vulnerable to eventual breakage.

Yeah, probalby not the way I'd want to go. Easier to just get a couple new terminal blocks and replace the existing ones. I just need to see if I can remove those little DC+ and DC- plastic pieces and attach to the new terminal blocks so it looks "oem".

[inetdog]

But if we can clip off some small strands to make ti fit, that would work? I'd be ok with that as long as it's safe.

As I noted, it is not compliant with the NEC. And if done improperly it can make the connection more likely to overheat or make the remaining strands more likely to break.
As long as there is strain relief on the wire to prevent it from being pulled on at the terminal, I would consider it safe, but of course I could not encourage it.
Be very careful not to scratch, nick or repeatedly bend the remaining strands, since that would make them vulnerable to eventual breakage.

[sensij]

Well, it looks like we kind of have to do new permits. I called up SolarEdge and the inverter will not accept anything bigger than 6AWG wire. An adapter would need to be used, which isn't shown on the permit, so that wouldn't pass either.

The only out would be if there are these terminal blocks that can be swapped out in the disconnect to accept bigger wire? Anyone know?

They exist. I don't know if they'd fit, and you should also buy the end cover. Check the catalog page for that part number. Same caveat as before... you are messing with a listed assembly, which violates the listing, and is not technically compliant. If you do it neatly, I would guess it is unlikely to be noticed.

Edit: Please do not clip the strands to make it fit in the undersized terminal block. Please.

[HX_Guy]

You can change wire sizes with a crimped butt splice with an insulating sleeve. With luck the set of splices will fit inside the terminal box, so no visible changes needed and the wire outside the box will be the proper size. You can rent of buy a hydraulic crimper for the connectors. What you do inside the terminal box would not necessarily be required to be on the plans.
The other common technique, not accepted by code, is to clip off enough small strands of the wire to get the rest to fit into the terminal.

I actually found this product here, that I think I could swap out the terminal blocks and it accepts 2AWG wire.

http://catalog.weidmueller.com/procat/Product.jsp;jsessionid=2E33891978DED432048B6E3666214A40?productId=(%5b1020500000%5d)&page=Product

But if we can clip off some small strands to make ti fit, that would work? I'd be ok with that as long as it's safe.

Regarding the red label, was that really supposed to say that the PV wires were "underground" or was it supposed to read "ungrounded"?

It sure WASN'T! It's supposed to say say "Ungrounded", just like this label should say 59.38A, not V...and 240V...not A. The inspection didn't catch any of it, but maybe I'll get lucky next round! Oh, and "Innerconnection" isn't a word.

[inetdog]

Hey, the most important thing is you know the physical design part is perfect. The wiring mostly
just proves you were right and the installer was wrong. Wiring isn't so hard to fix; you ought to
see how much rewiring I did. But you need more tools; use one once and its paid for.

You can change wire sizes with a crimped butt splice with an insulating sleeve. With luck the set of splices will fit inside the terminal box, so no visible changes needed and the wire outside the box will be the proper size. You can rent of buy a hydraulic crimper for the connectors. What you do inside the terminal box would not necessarily be required to be on the plans.
The other common technique, not accepted by code, is to clip off enough small strands of the wire to get the rest to fit into the terminal.

Regarding the red label, was that really supposed to say that the PV wires were "underground" or was it supposed to read "ungrounded"?

[bcroe]

The installer is still in the picture...fortunately or unfortunately. The inspector did say we could resubmit the plans if we choose, either options is fine with the city as long as the wire and conduit in place is the correct size for the system. The crappy part about redoing with #2 wire to match the plan is that the inverter only accepts #6 as the biggest size, so not sure how that would be addressed.

Oh, and running the PV wire through conduit on the roof...that'll be fun. Lots of panels will need to be removed to access it.

Hey, the most important thing is you know the physical design part is perfect. The wiring mostly
just proves you were right and the installer was wrong. Wiring isn't so hard to fix; you ought to
see how much rewiring I did. But you need more tools; use one once and its paid for.

[HX_Guy]

Well, it looks like we kind of have to do new permits. I called up SolarEdge and the inverter will not accept anything bigger than 6AWG wire. An adapter would need to be used, which isn't shown on the permit, so that wouldn't pass either.

The only out would be if there are these terminal blocks that can be swapped out in the disconnect to accept bigger wire? Anyone know?

[HX_Guy]

I don't know if resubmitting the plans will be a good plan since the Installer is pretty much out of the picture. It will be more work and more money but I feel to get the system passed and working just do what the inspector asked and make it match the permit drawings.

The installer is still in the picture...fortunately or unfortunately. The inspector did say we could resubmit the plans if we choose, either options is fine with the city as long as the wire and conduit in place is the correct size for the system. The crappy part about redoing with #2 wire to match the plan is that the inverter only accepts #6 as the biggest size, so not sure how that would be addressed.

Oh, and running the PV wire through conduit on the roof...that'll be fun. Lots of panels will need to be removed to access it.