These are the connectors they are for:
So as you can see, the PCI-e connector uses either 3x12v + 3xground or 3x12v + 5xground wires in the cable. I've red that optionally some of the wires can be used for some sort of regulation signaling but nobody really uses this functionality and as far as the power supplies and graphics cards are concerned, its fine if they are just 12v and ground.
For the 8P CPU connector, its always just 4x12v and 4xground as far as I know.
Now the reason I'm asking is because I've built some 8P CPU connector -> 2x 8P PCIe adapters which work well and I'm looking to build a whole bunch more.
What I want to do is to not bother with all the separate wires and just use a pair of 15AWG wires for the cable which I then split up for the separate pins in the connectors. The max current would be 25A which both the connectors and wires are able to carry.
From the PSU's that I've opened, I've seen that the 12v and ground wires all get soldered together anyways so there shouldn't be a reason why this would be bad.
Before I go ahead and do it, do you guys know of any reasons to keep the wires separate?