How to Diagnose Arc Fault

[mjp24coho]

I have been getting a recurring arc fault lately.  Any idea on how I can diagnose it to see what's causing it?  I've reset the Classic after each time, but it has happened a few times after.  It seems to be occurring after I've run my generator (through my inverter) to top the batteries off.  For reference, I'm offgrid and have a pre-wired epanel with (2) classic charge controllers and a Magnum 4000 off-grid inverter.

[Vic]

mjp,

Would not hurt to check and re-torque all cable connections,  especially on the DC side of things.

Have you tried adjusting the Sensitivity setting for Arc Fault -- a higher number should lower the sensitivity.

Just a drive-by guess.   FWIW,   Vic

[mjp24coho]

I increased the sensitivity by 2 from the default, but it still gave me the error a day later (after running generator support).  I haven't tried retorking all the DC connections, but can when I'm at my cabin next.  I'm trying to find any potential fixes before going up there.

[boB]

Did you reboot the Classic after making the Arc Fault adjustment change ?   It needs to be powered down and back up for that
to take effect.

Also, try upping both values all the way up to see if it helps.

Has is been working without arc faults or is this a new unit and has always done this ?

[mjp24coho]

Yes - I reset the classic after changing the sensitivity. I've had the classic for over a year, but the arc faults are anew occurrence in the past week.

[boB]

If you haven't changed things in your system much, such as adding new and weird loads or something like that, then
I would definitely look at the PV side of the system.  Check tightness of connections in the combiner, check for corrosion
of connections, etc.

It wasn't too long ago we had a customer that had the arc fault tripping a bunch and he found a connection that was arcing.

But sometimes a new and different inverter or an arc welder can cause it.  Things like that.

Yeah, it's worth at least a check of the wiring, breakers and tightness of screws, etc.

boB