Combiner box for SolarEdge 10kW inverter

[HX_Guy]

SolarEdge inverter is also limited to #6 wire so that shouldn't be a problem with that box.

[Amy@altE]

Dan, thanks, I do use the Wiley boxes a lot. I had stayed away from it since my original design was too complex for it, but even the pass thru box is now an option. I'll play around with cost and see if Wiley is a better option than Midnite.

HX, thanks for the reminder about the #6 for the inverter, that certainly ruled out my original plan of 1 combined string.

[labear]

Hey guys & gals,
I'm doing a self install of 33 panels & SolarEdge 7.6k inverter in about 30 days. This is on a new home were building and the panels are already setup (mounts installed) for 2 arrays (1 array w/ 9 panels on an RV roof and 1 array w/ 24 panels an adjoining roof) all South facing.
My question is; I read all your comments & replies re combiner boxes and am truely confused. The reason for the confusion is that this Solar Package is being purchased complete from Wholesale Solar. It does not seem they provide any junction boxes for the roof solar interconnections.
I am aware that there is 1 optimizer connected to each panel though I assumed that the 100' 10awg dual cable they provided (w/ MC4 connectors) for each array (2 qty cables) would come w/ all interconnection cables to the optimizer's and THUS there would be no need for any combiner box.

Can anyone weight-in on this question - assuming anyone is aware what the WholeSolar packages include???

thank you

[ButchDeal]

Junction box and combiner are two different things. You should not need a combiner with solarEdge, but might need a box.

[Amy@altE]

Since every installation is unique, "complete" packages are not necessarily complete for everyone. You need to talk to your sales rep to work out the details for your system, you may need additional components to make it work. Solar packages are a great starting place, but can never be sure to have everything for everyone. *EDITED You would not be able to have the 9 panels from the RV in one MPPT port, and the remaining 24 wired in 2 parallel strings of 12 into the other, because unless they are very low power panels, the 24 panels will exceed the 5250W per string limit. You'll need to somehow combine some from the roof with the ones from the RV. Talk to your rep for your options, that's what they are there for.

[labear]

Amy, YES good point re some of the main roof panels will need to be combined into RV roof panel array in order to keep the main roof array under 5250w. And yes, I'll double check this w/ sales rep. What is a MPPT port?
I assume you are reffering to SolarEdge inverter PV input(s)?
And just curious, why could I not have 9 panels (280w each) in 1 specific port?
As for what Butch said (Hi Butch and thank you for your reply); I'm still somewhat confused re the connection of panels to optimizers, then combining those into the dual 10 awg cable(s) they provide for each array. I knew I would need a junction box on the roof to connect the dual 10awg cables to the optimizers (set)... (Optimizers sets would be connection of each array set of optimizers into a parallel set, using some sort of interconnection-link cables which I assume they will provide w/ package) .
On this, the sales rep has been no help and just says wait for the "design" drawings and permits docs, which they provide w/ the package..... and that will explain everything.
Any thoughts on this???
As for the provided dual 10 awg cable sets (x2); they do come w/ a female & male MC4 connectors on one end (bare on the other. So would these then be plugged into something like a pass-through junction box on the roof?
I'm just trying to understand the overall interconnection of the system + getting my conduits inside into the roof jousts and as prepared as I can for the solar package - which I don't expect, nor will I be ready for, until late November.
thank you and awaiting for more feedback

[sunnyguy]

*EDITED You would not be able to have the 9 panels from the RV in one MPPT port, and the remaining 24 wired in 2 parallel strings of 12 into the other, because unless they are very low power panels, the 24 panels will exceed the 5250W per string limit.

Two strings of 12, neither of which exceed the 5250w per string. The input on the inverter does not have a 5250w limit, does it? Only based on the wire size limitation. Solaredge mppt is in the optimizers.

[ButchDeal]

The input on the inverter does not but the optimizers do have a limit, so you can't have strings over the watt limit.

[ButchDeal]

Amy, YES good point re some of the main roof panels will need to be combined into RV roof panel array in order to keep the main roof array under 5250w. And yes, I'll double check this w/ sales rep. What is a MPPT port?
I assume you are reffering to SolarEdge inverter PV input(s)?
And just curious, why could I not have 9 panels (280w each) in 1 specific port?
As for what Butch said (Hi Butch and thank you for your reply); I'm still somewhat confused re the connection of panels to optimizers, then combining those into the dual 10 awg cable(s) they provide for each array. I knew I would need a junction box on the roof to connect the dual 10awg cables to the optimizers (set)... (Optimizers sets would be connection of each array set of optimizers into a parallel set, using some sort of interconnection-link cables which I assume they will provide w/ package) .
On this, the sales rep has been no help and just says wait for the "design" drawings and permits docs, which they provide w/ the package..... and that will explain everything.
Any thoughts on this???
As for the provided dual 10 awg cable sets (x2); they do come w/ a female & male MC4 connectors on one end (bare on the other. So would these then be plugged into something like a pass-through junction box on the roof?
I'm just trying to understand the overall interconnection of the system + getting my conduits inside into the roof jousts and as prepared as I can for the solar package - which I don't expect, nor will I be ready for, until late November.
thank you and awaiting for more feedback

The solaredge inverter does not have two PORTS. It has to connections on an input bus. Two strings do not need a combiner with Solaredge, infact three strings doesn't require a combiner with solaredge. They have white papers on this but other than the SE10000 and SE11400 ( which have 3 inputs) the inverters only have two wire connections. So if you are not using the larger inverters, you would need a way to combine at least two strings.

[bcroe]

I just started designing systems with the SolarEdge inverters. I'm trying to find out what most people are using for a combiner box for the bigger ones, 10kW and up. I'm using 4 strings, and including the Rapid Disconnect kit, so I don't need a fancy disconnecting combiner box. Are most people just combining the 4 strings into 1 string and using a regular combiner box like the Midnite PV12, and using 4 fuse holders for the + and 4 for the -? Or does it make sense to combine the 4 into 2 strings, running 2 sets of wires back to the inverter? The current is so low, it seems fine to run the 1 combined string back. What say you with experience?

I wanted to mention, a PV12 handles 12 lower voltage circuit breakers, or 8 high voltage fuse holders. But it can actually take
12 fuse holders, if you turn around the top feeder combs to put the feed wires on the outside instead of the center. Bruce Roe

[Amy@altE]

Labear, I think others answered your followup question to me, but just in case... I shouldn't have called it MPPT ports, I was talking about the DC inputs to the inverter from the DC optimizers. The 7600W model has connections for 2 strings on it, that acts as an internal combiner. The 9 Optimizers in one string isn't a problem, it should be a high enough voltage and current for the inverter, the problem is the 24 into the other string. It exceeds the 5250W limit. You'll need to wire some of those 24 in series with the 9 on the RV, so it's not combining them in parallel, but adding them into the string of 9 in series. Then the 2 strings, each under 5250W, will be combined inside the DC Safety Switch in the inverter. Both strings do not need to be the same quantity, but neither can exceed 5250W. SolarEdge does have some helpful videos on their YouTube page. https://www.youtube.com/user/SolarEdgePV

[sunnyguy]

Labear, I think others answered your followup question to me, but just in case... I shouldn't have called it MPPT ports, I was talking about the DC inputs to the inverter from the DC optimizers. The 7600W model has connections for 2 strings on it, that acts as an internal combiner. The 9 Optimizers in one string isn't a problem, it should be a high enough voltage and current for the inverter, the problem is the 24 into the other string. It exceeds the 5250W limit. You'll need to wire some of those 24 in series with the 9 on the RV, so it's not combining them in parallel, but adding them into the string of 9 in series. Then the 2 strings, each under 5250W, will be combined inside the DC Safety Switch in the inverter. Both strings do not need to be the same quantity, but neither can exceed 5250W. SolarEdge does have some helpful videos on their YouTube page. https://www.youtube.com/user/SolarEdgePV

Is there a situation where 3 strings (12-12-9) would be preferable to 2 strings (17-16) when using optimizers? Maybe if the arrays are separated by a large distance?

[foo1bar]

Is there a situation where 3 strings (12-12-9) would be preferable to 2 strings (17-16) when using optimizers? Maybe if the arrays are separated by a large distance?

Only situation I can think of is if the string of 17 would be hitting the maximum power for the string.
And even then you'd have to look at how much of the peak is being lost compared to how much of the tails of production are being lost because the 9-panel string is not able to meet the minimums.

Or maybe if the 3 arrays are separated by a long long distance and you'd have to run 2 extra wires to one of the arrays. (the extra cost in copper could possibly make it better to do 3 "strings")

Both of those I think are going to be pretty unusual and I'd guess a negligible gain over a 17+16 setup.

solaredge has a nice software that is freely available that it'll let you plug in your arrays and it'll figure out what solutions are possible for you.

[labear]

Hi Amy & others,
Thank you for all your input on my Solar project. I expect that I'll proceed w/ 2 arrays (17+16) where one or the other (17 or 16) includes the 9 panels (w/ optimizers) on the RV garage roof. Just a note: the RV garage roof panels are only 18" ~ 2' away from the panels on the main garage roof. So I can only assume the cable wire lengths that will be provided from Wholesale Solar will be long enough to reach that set of panels.
Having prior knowledge & now confirmed by you guys; that I can wire the 2 arrays into the SolarEdge 7600 w/o other combiners.... is a good thing.
I'm still assuming though that I will not need some sort of junction box between the 2 garage roofs (since they are physically attached, just small space between the panel array sets)...........
Did anyone ever answer my question re suggested roof-jack & pass-through junction box for roof, for the dual 10 awg wires (and ground) which would connect to optimizer wiring chain(s)?
Note: I will have a 3/4" or 1" conduit already in place under the roof be the time I begin mounting panels. I'm thinking since I need to wire the RV garage array panels (x9) over to the main garage array, maybe it best I just run a single 1" conduit for both arrays.
Can you guys confirm that 1" would be enough for both sets (4 x #10 awg & I assume 2 #6 ground, one for each array)?
My last question is a followup to Amy's most recent comment;
So is it true that the panel optimizers are wired in series??
Of course w/o a drawing from Wholesale Solar as yet, I've been under the impression that all where in parallel??
Unless it's series/parallel (for some appropriate combining voltage & current requirement)??

thank you
labear

[foo1bar]

So is it true that the panel optimizers are wired in series??
Of course w/o a drawing from Wholesale Solar as yet, I've been under the impression that all where in parallel??
Unless it's series/parallel (for some appropriate combining voltage & current requirement)??

thank you
labear

Are you planning to do this as a DIY project?
If so, you need to learn more about how a Solaredge system is wired.
Usually optimizers have one side connected to a single module.
And the other side is connected in series with other optimizers to make a "string" of at least 8. And the string also has a maximum number as well (based on not exceeding the max amperage/power for the string

Can you guys confirm that 1" would be enough for both sets (4 x #10 awg & I assume 2 #6 ground, one for each array)?

1" of what type of conduit?
Search for "Conduit fill calculator" and you can calculate if you're within the fill allowed for a given conduit.
If you're using metal conduit (and you probably should be) you should plan on either running the ground wire outside of the conduit or plan on grounding bushings on the conduit at both ends.

Since it's 2 fairly close arrays on one structure (just multiple roof planes of the structure) you can probably run 1 ground wire that connects to both arrays.
BTW - you will need to have some sort of support for the wires going from one array to the other. Whether that's conduit or some other method. You can't have the wires laying on the roof.

[labear]

Yup- knew I'd need some sort of conduit for between roofs (arrays)... thank you
As for conduit (1") type; I was hoping I could use a HydroMaxx type (non-metatic) conduit.
Do you feel I could use HydroMaxx type conduit for 10awg lines carrying PV-DC (approx 2x5000w)?
FYI- I'm in California

[foo1bar]

Yup- knew I'd need some sort of conduit for between roofs (arrays)... thank you
As for conduit (1") type; I was hoping I could use a HydroMaxx type (non-metatic) conduit.
Do you feel I could use HydroMaxx type conduit for 10awg lines carrying PV-DC (approx 2x5000w)?
FYI- I'm in California

There's a good chance the inspector will expect metallic conduit. Arguably optimizer output wires aren't a PV source - but you'll have to convince your inspector of that or he'll say you are violating code.

If you use non-metalic flexible conduit, how will you keep it up off the roof? How far will it be above the roof?
Have you checked that you'll be OK for derating due to heat, taking into account your distance above the roof.

There is a lot you need to learn about in order to do an install - it's not impossible, but I strongly recommend that you do some reading and learning before you start this project as a DIY. I'd recommend hiring an electrician to help you with the install - they will (hopefully) help you stay code-compliant.