What are "hybrid cables" for you? The set has
- 1 x 24-pin ATX-3 cable
- 1 x 8-pole EPS cable
- 1 x 4 + 4 -pin EPS cable - 2 x 8-pin
- 2 x 8-pin PCI-e cable
- 1 x 6-pin PCI-e cable

The EPS cables and the PCI-e cables are not compatible; a different connector is used to prevent them from being plugged in incorrectly. This is due to the fact that the pin assignments for these two connectors are different, i.e. PCI-e only has 3x12V lines, whereas EPS has 4x12V lines.

Yes, that's what they are for...