I'm trying to decide if I need to purchase GFP device. Apparently, some MPPT charge controllers will have GFP built in, and some don't. I have tried to determine by reading the manual if the Growatt has GFP built-in. I found a mention of it in some of their grid tie products but can establish whether or not these all-in-one type units have the same feature. By ground fault, I mean detecting and addressing something like a positive wire touching the grounded panel in the panel array.