That is 400a per phase. The 600v is phase to phase. For a 600v wye, l/n would be 347 as would be the wild leg of a center tapped 600v delta although I have never heard of doing it. Typically you see 480v as the high end of "low voltage". (a multiple definition term itself)
So does that mean that for a 230V phase-phase (400V phase-neutral) system with a max current per phase of 160A, I actually can use a DH324NRK instead of the one in the previous link? Or do I have to go to the DH364NRK as I have 400V phase-phase so need the 600V capacity? Based on this cut sheet?
If you have a 240v 3p with a 160a computed load the xx324xxx sounds like it is your panel with a 200a breaker using the appropriate conductors. If you had diversity and non continuous loads you could step down to 175a