Length is important, but he said it's 8-10 ft to controller.
At this length, with 2*100W panels, #10 @11A will have voltage loss well under 2%.
4*100W in parallel require a thicker cable. Or go series with MPPT controller.
Yes, manuals of decent controllers over 20A suggest fuses both before and after. I chose to ignore panel fuse. Wire can carry more current than panels will ever generate. My roof is rubber, on a dry day there is nothing to worry and on a rainy day there won't be much current. My 24V panels in series never generate more than 8A total. 12V panels in parallel is a different story though.
Human body doesn't usually like currents over 1A. If anybody could explain why a short to ground may not happen at all, I'm listening.