I guess I'm confused about when you need overcurrent protection on the secondary side of a transformer rated less than 600v. Table 450.3(B) gives you two protection methods, "Primary only" & "Primary and Secondary". If I choose primary only, do I still have to follow the rules set forth in 240.21(C)(1) through (C)(6), which tell me when I need secondary protection? I guess what I'm asking is how do these two code sections apply to each other? Any help in getting me to understand this better is appreciated.