How to Center feed Emphase IQ7+ from a soladeck?

[ChrisBarrett]

I am designing a 33 panel system divided into 4 arrays. The first array has 11 panels, and the second array has 9 panels. I would like to center feed both of these arrays to limit VRise, but also just for the logistics of where to place the soladeck enclosures.

The question I have is how to wire the center feed. For example, if I have #10 THHN L1 and L2 coming up through the attic from the combiner box, I need to connect 2 wires to each L1 and L2 THHN. I'll have a Array1 Left and Array1 Right, each with L1 and L2 AND Array2 left and Array2 Right. <not combining the two arrays in the soladeck>

Is there a combiner terminal block that will fit on the soladeck din rail? I have been searching, but haven't found anything yet.
Thanks!

[ChrisBarrett]

So my question assumes that I'll be cutting a Q cable string and feeding 2 cables into the enclosure. I suppose you could field wire a q cable connector and connect it into the string that way?


Is this what would enable combining both sides of a string?

https://www.altestore.com/store/enclosures-electrical-safety/electrical-enclosures/combiner-pass-through-boxes/soladeck-ac-busbar-kit-2-circuit-p40767/?gclid=Cj0KCQjwiYL3BRDVARIsAF9E4Ge8O1uUSVM0QWWHqh9PkJtToSzEz0GRlAreuPaGoT_ROWdEs_EEkYcaAnYeEALw_wcB

[joemadsun]

Saw your question here as well. I'm center feeding as well. I am running raw Q cable out of the soladeck to a female field wireable Q connector and then connecting that to a portrait cable with one more connection in it than there are panels in teh branch.

[bob-n]

Chris,

Your question involves electrical advice. I am not an electrician but can refer you to a document that seems to answer your question.

http://www.backwoodssolar.com/media/pdf/Backwoods_Solar_2016_Catalog.pdf

From page 48.
"COMBINER BOX The combiner box mounts on the post of a pole mount, or under the eves for a roof mount. Wires from the solar modules connect together in the combiner box. National Electric Code requires each panel or each series string of panels to be wired to its own circuit breaker or fuse if there are more than two strings in parallel."

So if this is right, your four-string system needs more than a terminal block. You need a breaker per string if there are more than two strings. I think that the reason for this is Q-cable is only 12AWG and you don't want three strings putting too much current into the fourth string in a fault.

The dealer who is selling you the SolaDeck should also have appropriate breakers and terminal blocks. There are many DIN rail terminal blocks available from dealers on amazon as well, but one-stop shopping might be more convenient.

If in doubt, get advice from an electrician.

[Ampster]

I am designing a 33 panel system divided into 4 arrays. The first array has 11 panels, and the second array has 9 panels. I would like to center feed both of these arrays to limit VRise, but also just for the logistics of where to place the soladeck enclosures.

The question I have is how to wire the center feed. For example, if I have #10 THHN L1 and L2 coming up through the attic from the combiner box, I need to connect 2 wires to each L1 and L2 THHN. I'll have a Array1 Left and Array1 Right, each with L1 and L2.
cu
Is there a combiner terminal block that will fit on the soladeck din rail? I have been searching, but haven't found anything yet.
Thanks!

You need to pay attention to wire size and current. I think the IQ7 cable is 12 GA and only rated for 15 Amps continous with a 20Amp over current protection device. What is the combined Amperage of those two strings?
NOTE:
Per Enphase on page 11, the IQ string is limited to 16 IQ7s.

[ChrisBarrett]

Joe, thanks!

Bob,
Thanks for your info. I didn't want to describe the whole system for this single question but I can give a high level overview:
33 panels in 4 arrays on 4 different roof planes using IQ7+ micro inverters. The four arrays are fed by 4 soladecks. I have another question I am going to post regarding wiring in the attic, but to simplify I'll say from the soladecks I'll run #10 THHN down conduit to the Emphase Combiner box where each line is terminated at a 20A breaker. Then from the combiner #6 THHN out to the fused AC disconnect and from there to the customer side of the meter for a load side connection at the lugs.

I have two open questions I'm going to post about. Should I ask them in this thread, or is it better to start new threads?

[ChrisBarrett]

Ampster and Bob, sorry if I wasn't clear - I won't be combing the two arrays together. But both arrays will need to pass through this one box to head down to the combiner box in the basement.

[Ampster]

Ampster and Bob, sorry if I wasn't clear - I won't be combing the two arrays together. But both arrays will need to pass through this one box to head down to the combiner box in the basement.

Okay, there are DIN rail terminal blocks that you can buy. I have seen them at Automation Direct and other sources. If I understand you correctly you are using #10 to reduce voltage drop?

[ChrisBarrett]

Here is the site plan with some MS paint level labels, ignore the conduit going no where, there isn't going to be conduit on the roof You can see that Array 1 is split across two roof planes, and Array 2 is on one - but fed from the same Soladeck.

Soladeck locations.jpg

[ChrisBarrett]

okay, there are connector devices that fit in DIN rail. I have seen them at Automation Direct and other sources. If I understand you correctly you are using #10 to reduce voltage drop?

Correct Ampster, it'll be about 70 feet max for the furthest array.

[bob-n]

In that case, if you're just splicing wires, you don't need any terminal blocks. You can simply use wire nuts. Some people hate them, but done well, I'm told that wire nuts are fine.

If you want the convenience of a terminal block, type "din rail terminal block" into Amazon's search and you'll find a few different varieties available. The first that came up for me, Dinkle DK2.5N (photo below), claims to be UL listed and is rated 12 AWG 20A 600V. I believe that they sell you one 20-circuit block that you can separate it into a few different two-circuit blocks, one for each of your SolaDecks. If you are using 10 AWG wire, they also have larger terminal blocks, likeDinkle DK10N, rated 6-20AWG up to 60A.

711-CqVwbcL._SL1164_.jpg

By the way, SolaDeck is great if you are going through the roof into the attic. If you just need a junction box, it might be overkill. There are many UL rated junction boxes that you can place on the roof or in the attic that are cheaper.

Feel free to keep all related questions in one thread.

[ChrisBarrett]

Thanks Bob!

The reason why I thought terminal blocks were required was due to 690.32H -
Flexible, fine- stranded cables shall be terminated only with terminals, lugs, devices, or connectors in accordance with 110.14.


However, now I see that I have the 2014 NEC here, so I need to grab 2017 NEC and read 690 there, as well as 110.

[bob-n]

Good point on 690.32H. You're probably right. That's why I started this with "I am not an electrician."

I don't know if the Dinkle terminal blocks meet the 110.14 requirement. The Dinkle website has some information, but I can't match it to the Enphase description. I just held a chat session with Enphase support and they didn't know, either. Strange.

[ChrisBarrett]

Next open question I have:

Wiring through the attic. Am I crazy for wanting to use 10/2 romex? I can't make up my mind which is worse (not even mentioning meeting code): running the NM through the attic and then down inside an adjoining wall with the garage to the basement to the combiner box... OR installing conduit in the attic and out the soffit directly down to the meter/service and running #10 THHN through it.

I have not asked the inspector yet if he would find NM permissible in this installation. Thoughts, experiences, opinions?

[Ampster]

Next open question I have:

Wiring through the attic........
I have not asked the inspector yet if he would find NM permissible in this installation. Thoughts, experiences, opinions?

My experience is that it is a local juridiction issue. On a professionally installed system there was some steel flex that they used to get to second floor and then emt to the roof. I know that jurisdiction wanted only emt throughout but they never saw the flex and the emt was visible with lots of labels. In another jurisdiction same thing about all the visible piping was emt but the inspector must have seen the aluminum flex from the NB into he wall and to the main panel.