Such a data can be found in instruction sheet, as in attachment for instance.
The values expressed as Mxx (e.g. M6,M10, M12) means there is a hole in busbar for connecting the cable with cable lug.
So max cable cross-section then depends on the cable lug you buy.
If you buy cable lug e.g. Cu120 - 12 (see picture) it means that this lug is dedicated for 120mm2 cable and has hole prepared for mounting using M12 bolt.
The values expressed as Mxx (e.g. M6,M10, M12) means there is a hole in busbar for connecting the cable with cable lug.
So max cable cross-section then depends on the cable lug you buy.
If you buy cable lug e.g. Cu120 - 12 (see picture) it means that this lug is dedicated for 120mm2 cable and has hole prepared for mounting using M12 bolt.