Ground Fault Failure

[MichaelR]

   The system has two Classic 200 charge controllers.  Everyday they stop charging and show a "Ground Fault" on the display.  I need to hit the "main menu" button a number of times then the display shows "charge".  I then hit the "status" button and the controller resets and starts charging the batteries.  It seems to do this each night when the sun goes down.  You cannot reset the controller if there is no daylight.  The system has been working fine until recently.   Not sure what has transpired.  The lightning arrestors are still blue so there has not been a lightning strike.
   If anyone has seen something similar or knows how to solve this, any advice would be greatly appreciated.  Thank you.

Regards,
Michael

[MichaelR]

I guess I was wrong about the not occurring during daylight.  I was looking at it and it failed again.

[ClassicCrazy]

If you think everything in the system is okay - you can just disable ground fault in menu.
But I don't have any idea why yours is going to ground fault.

Larry 

[boB]

You might try checking to see if you have an actual ground fault.  It may be that you do.

How it works is that if there is current between the PV array (usually PV+) and ground, then a 3/4 amp resettable fuse inside the Classic will open up and that is how the ground fault is triggered.

You could use an amp meter to measure the current through your Classic's ground line to see if that might be on the edge of triggering it.

When the fuse opens, you may not measure much current, if any though.

When it is triggered and you are seeing the error, you can take a DC volt meter and measure voltage between the negative battery/PV line and ground.  If there is a significant amount of voltage, then you may very well have a real ground fault somewhere.  This would also be measurable with the current measurement.

IF it is real, then you might want to know about it

boB