Isolation faults happen on PV systems when DC current leaks to ground. It can be caused by a number of issues like damaged or pinched wires, defective optimizers, or an inverter fault. In the new Residential Field Operations & Maintenance course, HeatSpring instructor Keith Rohman walks students through solving the issue from arriving onsite to a non producing solar array and running inverter diagnostics, calculating where the fault is located on the string, and correcting the issue. Here’s a short video excerpt of his process or check out the transcript below. Want to learn more? Consider enrolling in Residential Field Operations & Maintenance to follow along Keith as he fixes residential solar site issues.

Keith teaching out how to calculate where to locate the isolation fault.
This is from the Residential Field O&M course prior to the video excerpt.

So we ran our diagnostics. We got a percentage. We did the math. We know where we should probably start our investigation process on the roof. We head up to the roof and where are we checking first? Between the seventh and the eighth panel. Well look at that. 

This image is literally between the seventh and the eighth panel. Without even having to lift a single module, we were able to visually find this fault. 

Now, it’s not always this easy, but this is just a really great example that can show you the tools you have at your disposal and the electronics that are available to really save you time on site, and to really help with the troubleshooting process. With our isolation test on the inverter and with our visual inspection, we have successfully located the fault.

Now it’s time to repair the fault. So now that we have located the fault with the visual inspection and after running our isolation test and doing our diagnostics within the inverter. It is time to discuss repairing the fault. 

Want to learn more about how to repair faults? Enroll in the Residential Field Operations & Maintenance course today!