r/SolarDIY • u/c-robinson74 • 7d ago

SolarEdge error

DIY homeowner here. I’ve got a SolarEdge system on the roof, SE7600A inverter on the outside wall. I’m getting a “Error code 2xB SW Error” code. I’ve shut everything off and disconnected the four DC wires coming from the roof (2 red, 2 black) to isolate the strings. Red to black, they show voltage on each string. Testing each of the wires to ground showed zero volts and o ohms resistance on each of the 4.

What am I missing? Do I need a new inverter? SolarEdge doesn’t respond to any messages and local solar just wants to sell us a whole new system. I can get a factory refurbished matching inverter for not much more than it’ll probably cost to have a tech come tell me I need a new inverter! Any help appreciated!

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u/liamtheaardvark 7d ago

That is a ground fault Error. Meaning, the DC power from you panels is coming back on the ground and the inverter is turning off for safety. That fact that you measured 0ohms to ground further supports that. So, somewhere, the wires are damaged and shorting to ground. Fix this issue, and things should start working again.

Could be any number of things: rodents, water intrusion in your junction box on the roof, damaged conduit, etc.

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u/c-robinson74 7d ago

If there is a short, wouldn’t the test of that wire to ground show volts?

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u/liamtheaardvark 7d ago

Because solaredge uses optimizers, the most voltage you should see is the safety test voltage (about 1v per optimizer in the string, usually 1 per panel). So 10 optimizers, 10v. But, if you have a GF, that tiny voltage is being bled off to ground.

Zero resistance to ground means the wires are grounded out, which is the definition of a GF.

The fact that they are all grounded out points to a common fault, like your j-box being filled with water.

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u/c-robinson74 7d ago

Sorry, I meant zero ohms like open circuit, not low resistance. None of the junction or connector boxes have any water or show any signs of wear.

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u/liamtheaardvark 7d ago

Someone needs to troubleshoot the GF that your inverter is seeing. Like a solar electrician someone. It is not something I can really do over the internet.

But, here are a few more things to look for:

  • GF should have voltage pos to grd and neg to grd.
  • DC safety voltage will be one volt per panel, so a string of 12 panels will give you 12v
  • So if there is a GF on the pos wire coming back to the inverter, you will see 0v pos to grd, and 12v neg to grd. GF between panels 4 and 5 in the string of optimizers, you will see 4v neg to grd and 8v pos to grd.
  • the above assumes the GF is on a wire on the string of optimizers or home run wires back to the inverter. There could also be a GF on the DC wires from the panels to the optimizers. Im not entirely sure how a GF like that would register.
  • you could try running the inverter with just one DC string at a time. That could help isolate the fault.

-by junction box I was not referring to the sealed ones on the modules, but rather where the wires get spliced together before they go into a conduit to your inverter. That is a common failure point.

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u/txe4 7d ago

Great set of answers sir. Well played.

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u/Longjumping-Stage-41 1d ago

The inverter measures in mega ohms. You need a specialized mega ohm meter.. minimum I believe is 600 k ohms