Was looking at Xuba feedback and found your question re solar fusing.
Look at the fuse amperage rating on the panels. If you are connecting panels in parallel then need to be seperately fused if the current of the others in parallel can exceed the fuse rating on the back of the panel.
EG connecting 3x 250w 40V 8A panels up in parallel. The panels are rated for 15A fusing max. Therefore all 3 need to be fused because if one has a fault and shorts, then 16A will flow through it which is above the fuse rating.