Ground faults are a notorious issue with PV installations. Essentially you have either a positive or a negative connected to ground. NUMEROUS causes can trigger a ground fault. DC wires pinched under the array, wires landed in the wrong terminals, precipitation triggering a ground fault, and on and on. 


The ground fault will need to be resolved before the system can be energized. 


PV-ISO-PRO01 - Negative wire is connected to ground

PV-ISO-PRO02 - Positive wire is connected to ground


If no ground faults are discovered then the fault is internal to the inverter and it will require an RMA. 


Troubleshooting


Disconnect all the DC inputs from the inverter. Measure DC voltage from all DC connections, positive and negative, to ground. The measurements should bleed down to a safe level less than 10vDC, and eventually go to zero or close to it. If any of the measurements don't bleed down, or are greater than 15volts, the system has a ground fault that will need to be found. 


If all the DC inputs are good, try landing them one at a time at the inverter and attempting to start it. If the inverter turns on with a known good DC input in every terminal, then there is no further issue, or the ground fault is intermittent. 


If the inverter still has a ground fault despite all the DC inputs being good, then the fault is internal to the inverter. This can be verified by connecting all the DC inputs and measuring DC voltage to ground. This will show that the failure is internal to the inverter.