HDD 4plug power cables BLACK WIRES?!

[Phrik]

I'm wrapping up a set of cables from my PSU...

I had to cut to make it shorter.... but I forgot to put a marker... is it bad if I end up MIXING the BLACK WIRES ?

Aren't those just ground wires ?

Help please ?!?

 

[Frank4d]

PSU black wires are all the same.