Wiring Two SolarEdge Home Wave Inverters Together

Elroy · November 2023

Hello, I've currently got a single 3800 watt SolarEdge inverter, along with 16 ground-mounted solar panels (two strings).

Basically, a one-line is:

Solar Panels ---(two strings, 4 wires)---> Inverter ---> Fused (60a) Cutoff Switch ---> Backfed 30a breaker.

I'm wanting to double what I've got. I've already got a second SolarEdge inverter (identical to the one I've got), and my solar panels. I'll be putting pipe in the ground this Saturday.

But, I just want to verify that I can just wire the AC output of those inverters together in my gutter box. Basically, I'm wanting this:

Solar Panels ---(two strings)--> Inverter#1 \
>----- AC Lines (L1,L2,N) ---> Fused (60a) Cutoff Switch ---> Backfed 60a breaker.
Solar Panels ---(two strings)--> Inverter#2 /

I'll upgrade all the AC wires to #6AWG. And I'll use three-way lugs in the gutter to put those together.

DOES THAT LOOK RIGHT?

TIA, Elroy

ps: All grid-tied.

SumPower · November 2023

Wire size, 16 amps x 2 = 32 Amps. Continuous load is multiplied by 1.25.

So 32A x 1.25 = 40 Amp rated wire minimum.

If you have voltage drop to consider a #6 cu is good like you have.

Depending on the code cycle your jurisdiction is on the breaker size at the main panel may need to be adjusted lower.

If you have a 200 amp main, then a maximum of a 40 amp breaker would be allowed for your grid tie feeder at the main panel.

If you have a 175 amp main breaker, then you could use a 65 Amp breaker at the main panel for your grid tie.

Divide breaker size by 1.25 to find max. allowable continuous inverter current. With a 40 amp breaker the max allowable amps to feed to the grid would be 32 amps.

All this is dependant on the code cycle you are on.

Elroy · November 2023

All I'm really wanting to know is if it's correct to tie the AC side of the two inverters together as they're getting to a single back-fed breaker.

Elroy · November 2023

@SumPower: Thanks for bringing my attention to the 120% rule! I've done more calculations, and a 40 amp breaker will get done what I need to do. I didn't realize there was that limit, but 40 amps seems to squeak by.

SumPower · November 2023

Elroy said:

All I'm really wanting to know is if it's correct to tie the AC side of the two inverters together as they're getting to a single back-fed breaker.

Yes, it will work. Just as long as you use 75° C rated conductors and lugs, Before I retired I used a lot of Polaris lugs.

https://www.platt.com/p/0286638/nsi-tork/multi-tap-connector-3-port-black-insulated-14-4-awg-1-sided/662381910011/nsiipl43

BB. · November 2023

Need to look at the installation requirements... (Actual manual, your country, local codes, etc.).

The typical requirement would be for 2x 20 amp breakers installed at the opposite end of the main panel inlet breaker (opposite end of internal panel but bars).

Generally, a single 40 amp breaker would exceed the branch circuit wiring requirements for a typical {not large) gt inverter.

Note, if this is North America, then you would have a 2 pole breaker for 240 VAC circuit (120/240 VAC split phase power).

And 2x 20 amp 2 pole breakers.

Details matter here.

Bill

SumPower · November 2023

As always, very good comment BB!

My post above only works if the (2) griid tied string inverters are run to a a sub panel first. Then to a main panel.

BB. · November 2023

Yep--A sub panel with (at least) 40 amp feed and 2x20 amp breakers should do it... You may have labeling requirements (caution solar power, etc.)...

-Bill

Wiring Two SolarEdge Home Wave Inverters Together

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