Wiring unlimited DC grounding - contradiction

DIY
, ,
22

The point of NOT grounding the PV negative cable is that this prevents currents other than the PV current from flowing through this cable. This can cause either a ground loop, or some hopefully small voltage offsets. However, in the event of a fault, where the battery positive is accidentally grounded, LARGE currents may flow though the MPPT negative cable and the PV negative cable to the ground point. These cables are normally much smaller than the battery cables, and may not be able to take the current due to the fault. This may cause overheating or fire conditions in these cables before the battery fuse blows.