Combiner box fuse/breaker choice

[MarkSolar]

Looking at Midnight Solar MNPV3 combiner box. I have 3 strings, Vmax= 400v, Imp= 10A. Trying to choose the right breaker/fuse, there are so many choices. It looks like breakers are 150v, so I don't think I can use those for my strings. The fuses are 600v, so is that what I should use? And do I need breakers for 3 strings, can I just combine the 3 strings and feed into DC disconnect?
tnx

 

[Tecnodave]

The midnite PV breakers are available in 150, 300, and 600 volt but they are 1 space,2 space, and 4 space, for 3 ea 600 volt breakers, 12 spaces, pretty big, Midnite does make a MNPV-12 combiner box, its pretty large , you should consider midnite touch safe fuse holders in a MNPV3 combiner for your use, but that may not fit your needs, do tell me a bit more about what you are doing, grid tie i assume, what kind of inverter, transformer or transformerless, brand of inverter tells me much, will combiner be at array? details please, yes you do need 3 ea. breakers or fuses. three strings is a safety hazard that i will explain more if needed, 2 strings in parallel is ok but not 3 strings in parallel with no fusing

david