Thanks for pointing this out. Thats not a good thing. One would need special PSU's that have different 12A-Outputs since a high wattage PSU with only 1 or 2 such channels used with Y-cables would hurt the miners when i understand it correctly.
Its a good thing i didnt buy more psu's yet but others might have bought wrong ones. Or is there a workaround for this?
You misunderstand. The information you've been given here tells you to use solid copper wires Awg 12 or 14 to bridge the board terminals and not to exceed 20 amps between the connectors on the boards (240W).
If you stick to this, nothing you do with the PSU cabling can exceed these limits and damage the boards directly. Of course, with such high loads if you aren't safe and wise its entirely possible to melt upstream connectors and cause a fire risk, or otherwise overload your PSU rails depending on its design.
@Burnin: If the tracks between connectors are rated 20amp does this mean the board can take its own requirements, say 8 amps plus passthrough a further 16 amps between the connectors, subject to not overloading the PCIe connector itself.