That whole CCA is not okay thing... yeah. If I have an aq 120.4 that has a fuse rating of 80, I'm going to use some knu 4 gauge cca which is roughly $0.60 cheaper than their ofc and will do what I need. Since the cca is rated for 100 amps and the ofc is 150, do I need the extra 50 if I'm not using it? Not really. Why is CCA not okay here? Seems perfectly fine for me.