[RE-wrenches] Repetitive and unknown arc-fault codes with this combination...Sunpreme bi-facial and Fronius IG

[August Goers]

Howard,



We haven’t installed Fronius inverters for a while, but I have some similar
experience with SMA and ABB arc-fault inverters. In only one case did we
have an issue where we actually had a workmanship issue – we found an MC4
connector where the terminal wasn’t fully seated in the housing. We had
another case with a SunPower array where we had to update the firmware in
the SMA Tripower because it was falsely tripping. We had many sites with
ABB/Power-One inverters where the arc sensors needed to be replaced. We
have a few sites with intermittent arc faults that were reset and haven’t
occurred again – I still don’t know what caused those.



After researching and speaking with tech support many times, I believe that
it is also possible that an AC-side arc or surge can cause an arc fault
trip. Examples could be a well pump surging, a old treadmill or other
appliance, faulty breaker, grid issue, etc. It seems unlikely, however,
that this is your case if the same problem is occurring on two different
sites.



All that said, I think you are on the right track in thinking it might be
an issue with the Sunpreme modules or a compatibility issue between the
Fronius and Sunpreme. You may need to get the manufacturers involved. If
they know what is good for them, they will give you ample support to fix
the problem.



Good luck!



Best,



August



*From:* RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] *On
Behalf Of *Howard "Scot" Arey
*Sent:* Thursday, June 18, 2015 5:31 AM
*To:* re-wrenches at lists.re-wrenches.org
*Subject:* [RE-wrenches] Repetitive and unknown arc-fault codes with this
combination...Sunpreme bi-facial and Fronius IG



I need some help please!  I’m quickly losing credibility with two of my
customers.



We have two installations with Sunpreme GxB 350 bi-facial modules and
Fronius IG inverters.  They keep throwing Error code 240 – arc fault on the
Fronius IG.



We’ve been up and down these installation three times checking connections,
replacing connectors, tightening connections, checking for chafed wires.
Nothing to cause any visible angst.



The team here is wondering is perhaps the module itself might be the source
of the problem, with some DC arcing inside the J-Box.  Any thoughts?  We
can’t open the j-box on an broken module (be careful handling frameless
glass on glass modules J) because there doesn’t appear to anything
accessible with modern potted j-boxes.



As for the conditions when we get these arc fault codes – typically the
peak of a sunny day when they’re making max power.



Each of the installations is a bit different. On the 7KW install with
Fronius 7.5, we’ve run the two strings (10 modules each) back to the
inverter separately.  On the 10.5KW install with the Fronius 10.0, we ran 3
strings of 10 to a combiner box, then one set of conductor back to the
Fronius 10.0 where we used the distribution plate to spead the amperage
across the six string input channels.



I’m stuck – any thoughts on other potential arc-fault causes?



*Howard “Scot” Arey*

254-300-1228

scot.arey at solarcentex.com



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