10kw SolarEdge String configuration

[skanmyth]

I am planning on DC wiring of my grid tied Solar Edge system. Below is my plan for solar arrays and strings

13 panels - array A
14 panels - array B
4 panels - array C
9 panels - array D

Array A,B and C is 3 sides of my main roof Array D is above garage 10 feet away from array A,B & C

String 1- I am thinking of connecting 13 panels from array A and 7 panels from array B can be one string with total of 20 panels.
String 2- I am thinking of connecting 7 panels from array B and 4 panels from array C and 9 panels from array D can be one string with total of 20 panels.

String 2 Array D is 10 feet away from main roof array B & C how do I connect from last panel from array C to first panel from array D? can I extend the wire from optimizer and connect continues? Or should I keep array B 7 panels & array C separate string and array D separate string itself and use a combiner to connect the 2 sub strings into one 20 panel string before connecting to inverter?

I am new to this I need help from guys have installed SolarEdge system.

[emartin00]

I think you are adding a whole lot of complexity with those last 2 panels in Array D. Yes, you could do it, but I don't really think it's worth the extra parts and effort.

You would need to run 2 different strings from Array D, 1 to array A and the other with the last 2 modules over to Array B. You should be able to use extension cables, but again, it's adding a fair amount of cost and complexity.

[acamato]

Did you download the SolarEdge software? You can setup the arrays and strings in it and it will tell you if the strings are within the limits for the inverter.

[greenconception]

Green Conception - Solar Energy Experts

Hello,

What is the wattage of your panels?

[Panelmal]

Hello,

What is the wattage of your panels?

This, and what wire are you planning to run? Sounds like you need 1000v PV wire which I highly recommend. Little memory and very thick insulation.

[skanmyth]

Did you download the SolarEdge software? You can setup the arrays and strings in it and it will tell you if the strings are within the limits for the inverter.

Yes, it gives an option for 3 strings but in reality I am thinking array B can be split into 2 strings and keep as 2 strings in total would it be more efficient to have more panel connected than less panel per string?

Below was the suggested string configuration by software

Inverter 1: SE10000A-US
String 1: Main South: 13 x P300
Main north: 4 x P300

String 2: Main West: 14 x P300
String 3: above garage: 9 x P300

Thanks

[skanmyth]

This, and what wire are you planning to run? Sounds like you need 1000v PV wire which I highly recommend. Little memory and very thick insulation.

250w panel. have not decided on wire what wire should I be using ?

[Ben25]

If you use 3 strings, you need a fused combiner. I would use 2. More wire off the roof but less equipment.

[skanmyth]

10kw 39 panel system.jpg

Attached is the layout of the roof and panels some changes compared to initial plan. Array C have been changed to 3 panels total panels is 39 now panel have been changed from 250W to 255W.

Array D is above garage I think there will be 15 to 20 feet away from first and last optimizer from Array D to closest optimizer in Array A. If I am connecting Array A and Array D what size wire I should use? what is the maximum length allowed to extend wire between optimizers? Optimizer I will be using is P300.

10KW invertor is located top right side (North East side)

I want to have only 2 strings dropped to inverter from roof what would be the best way to configure the strings with less materials?

I will be starting to install my project next week.

I need experts help who have installed Solaredge and have knowledge with extending optimizer wires.

[sensij]

39 * 255 W = 9945 W. Maximum power per string is 5250 W (or 25 panels), so running this as two strings looks possible.

I'd agree the cleanest way to do this would be to take the 9 D panels and combine them with 10 of the A panels to get a 19 panel string (4845 W). The remaining 3 A panels combine with the B and C for a 20 panel string (5100 W).

SolarEdge design voltage is 350 Vdc, so the design amps for the 20 panel string is 5100 / 350 = 14.6 A, while the amps for the 19 panel string is 13.8 A.

Let's assume you are using conduit to make the connections between arrays, and for the homerun to the inverter, and it is mounted something between a 0.5" and 3.5" off the surface of the roof. The 2011 NEC temp adder for that is 22 deg C. Let's say your max design temp was 34 deg, that bumps you up to 56 deg. Let's also assume you are using conductors with 90 deg insulation, your ampacity correction just barely lands at 0.71 [2011 NEC 310.15(B)(2)(a)].

MC4 connectors are good for 30 A, so termination rating should not be a factor if they are used.

12 AWG base ampacity w/ 90 deg insulation = 30 A * 0.71 = 21.3 A.
1.25 * 14.6 A design amps = 18.25 A

21.3 A > 18.25 A, so the 12 AWG conductors are OK.
20 A termination rating for 12 AWG (60 deg) > 18.25 A, so properly installed wire connectors are OK for the transition.

Voltage drop of 14.6 A through 25 ft of 12 AWG = 0.33%, so no reason to go larger there. There is no "maximum length" that cannot be compensated by sizing the conductors larger.

I would suggests using 12 AWG PV wire for any connections you need to make from one optimizer to the next within a string, then transitioning through a junction box into conduit with 12 AWG TWHN-2 for connecting one array to another.

If you run both strings together through rooftop conduit for the run to the inverter, you'd have another 0.8 adjustment for 4 current carrying conductors in conduit. That would drop the ampacity of 12 AWG to 21.3 A * 0.8 = 17.0 A... too low, so you'd need to bump up to 10 AWG for that section (if all the assumptions above are accurate).

[skanmyth]

Thank you for your detail reply sensij

What size grounding wire should I be using?

Thanks

[emartin00]

Thank you for your detail reply sensij

What size grounding wire should I be using?

Thanks

If it is unprotected (not in conduit), it must be 6AWG. You should be able to use 10 or 12AWG in conduit.

[skanmyth]

I had an electrician to give me a quote to run the two strings to run from roof to inverter and complete AC connection to grid. Electrician suggested to put a combiner box in roof with breaker. Do I need a combiner box with breaker? or should I be using a junction box to connect from roof to inverter?

[Ben25]

According to Solaredge you can combine 2 strings unfused on the roof. No need for any breakers. Just make sure the wiring to inverter is properly sized.

[skanmyth]

According to Solaredge you can combine 2 strings unfused on the roof. No need for any breakers. Just make sure the wiring to inverter is properly sized.

255w X 39 panels 2 strings will be combined on roof and will be running #8 wire about 25 feet inside pvc conduit to inverter is #8 should be fine ?