Originally Posted by klassic
I thought that's what you were going to do, when I asked if you were putting in a fuse.
I have read that it is recommended to have a fuse between the combiner box and the charge controller to prevent damage to the panels. I initially thought it was clever to put it inside the box. While I am waiting on more parts, I second-guessed the placement and thought it better to have the fuse accessible from the ground.
I have also read that individual fuses for each panel before the combiner box between the panels and charge controller are not required for installations of fewer than three panels wired in parallel. However, individual fuses for each panel before the combiner box are required for installations of three or more panels wired in parallel.
The manufacturer typically provides the fuse rating for each panel on the label. For the fuse between the combiner box and the charge controller for panels wired in parallel, the size is determined multiplying the sum of the Isc (short-circuit current) for each panel by 1.56 and then rounding up to the next size commercially available.
I purchased the 35A fuse because it is the next size commercially available for an ANL fuse block.
For example, the Isc of my 150W panel is 9.08.
Two panel setup:
(9.08+9.08)*1.56=28.32 (and I rounded up to 35A fuse)
I hope this is helpful.