Problems with Arc-fault breakers tripping after PV install

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Jrynes

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Arizona
Out of the hundreds of installs that I've done here in AZ, three have had problems with Arc-fault breakers tripping after install. The first 2 happened quite awhile after commissioning. So it wasn't easy to prove that it was our PV system that was causing it. The third however, started happening the night after the commissioning. It only happens at night when the inverter has shut down. If we turn the AC disco off at night no breakers trip. Turn it back on, they trip again. After talking to SMA ( SunnyBoy inverter), they had never heard of the issue and we came up with the solution to remove the neutral out of the system. We swapped the jumpers in the inverter and away we went. i thought for sure this was going to fix the problem. That night they still tripped. Two out of the five that are in the panel. All grounding is good. EGC bonded in, to, and out of every box, and a #6 bare GEC ran outside conduit and crimped to house UFER. I'm at a loss. Any ideas guys? Thanks. Oh yeah, and I already replaced all the breakers once.
 
. . . That night they still tripped. Two out of the five that are in the panel . . .
Welcome to the Forum! I am compelled to inquire, are the AFCIs GE, or are they the other three (CH, SqD or Siemens). I'm guessing the other three.
 
The breakers are Siemens.
Are the Siemens LED codes reporting a consistant ground fault, arc fault, or overload condition? Or does it vary? Or are these branch-feeder type AFCIs without LEDs?

Of the four manufacturers of combination type AFCI, only the GE CAFCI MOD 3 does not have the "ground fault sensing" component in its circuitry. IMO this is combination type AFCI two point oh. The GE is pure arc fault discrimination without the need for the sledge hammer of ground fault sensing.

May i suggest ruling out, or confirming, ground fault tripping, by substituting one of the AFCIs with a GE.

The GE CAFCI MOD 3 is the commonly available single pole AFCI that has been available from GE for over a year now. The phrase "MOD 3" is in tiny light colored print on the shroud at the breaker handle.
 
damn arc fault breakers again!

damn arc fault breakers again!

I have read that the principle used in arc fault breakers is to look for high frequency energy at very high harmonics of 60Hz. But that is exactly what you get out of inverters and universal motors like vacum cleaners.
A neighboring establishment does arc welding, and that trips all arc fault breakers in the neighborhood (mine are GE).
The whole idea of arc-fault breakers is flawed. What if I want to make sparks?
 
A neighboring establishment does arc welding, and that trips all arc fault breakers in the neighborhood (mine are GE).
Interesting.

Have you had your GE breakers more than 1-1/2 year? Or can you see "MOD 3" on the face?
 
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