How much space between cables is enough?


I understand that proximity between power cables and interconnects or power cables and power cables is a problem, but is there a rule of thumb as to how much space is required to NOT be a problem. 1/2", 1", 6"? Also, are all cables the same? I would assume that the higher the current, the more isolation, but belief and reality are seldom the same.
128x128tony1954
If I thought I could hear the difference, I might be willing to spend the hundreds to thousands of dollars on the fancy vibration isolation gizmos but I'm pretty sure I wouldn't.  I will say that putting those  E.V.A. Anti-Vibration Pad's under my subwoofer improved its sound immensely.  Instead of the booming rumbling unmusical beast it was, it became tight and a pleasing companion to my Magnepan 1.7's.  But putting those same pads under the 1.7's deadened the sound.  It makes sense that tube amplifiers should have vibration isolation so I have them under that too.  So I agree, listen and you may know, but some of us operate with more of a budget constraining our options.  I'm getting the Tekton Moabs in 5-6 weeks and it will be interesting to try the EVA pads under them.  Probably they will deaden the cabinet so I'm thinking of having a board or granite slab resting on them and the Moabs on top of that on spikes.  That is a more realistic option for me than throwing $600 at the  Isoacoustics Gaia II Speaker Isolation footers.
@millercarbon telling us how great his system is again. He is a broken record. Oh! and look at the photos. He's so proud, he wants everybody to know how cool he is.
The EVAs are similar to AV Room Service's EVPs.http://avroomservice.com/evp-2/I know these work. Also recommended by Jim Smith (Get Better Sound).
The only way to take the floor completely out of the equation is to suspend from the ceiling.  The gauge of the monofilament should de commensurate with the weight of the cable.