On one leg or two legs?

The length of dedicated ckts, one to the other, is superfluous. Arbitrary. Only really extensive runs of #12 romex (which is likely what will be used, unless otherwise specified) need to be addressed by increasing the wire gauge a step up.

This is not a common circumstance however. Even huge homes, or multi story homes, have additional sub fed panels these days, thus reducing the lengths of runs required. And thereby keeping the gauge of wire accordingly employed.

Commercial & industrial applications can vary some here, but residential installations seldom if ever need to address voltage drop issues by up scaling the wire type being used.

You can request the use of shielded cabling to further remove the ckt from ancillary or spurious artifacts… adjacent EMF, IHF, IM, etc. Again, I think this is overkill. If the runs do encompass higher current carrying supply lines, like HVAC, then it would be a more valid consideration… or if you simply wish to throw more $$$ at this… then by all means feel free.

I’d say save your money for conditioning, or other things.

Conductor sizes, load requirements, and max length specs can be found here:

http://www.powerstream.com/Wire_Size.htm

The lenght is about 8 ft. As you guys recommend i will get the Romex wire.

Blindjim,
Just curious.... Why did you spend big bucks for Shunyata Python VX and Shunyata Research Taipan helix Alpha power cords? I believe the wire gauge in the cords is equivelent to #10 awg. For the length of the cords you could of more than likely got by with 16 or 14 ga wire.

Looks like Houstonreef's branch circuit run is only 8' long. #14 awg would be plenty big.... But I would advise him to still use #12 ga.

By the way the ampacity rating for #12 awg cu is 20 amps whether stranded or solid. #10 awg cu is 30 amps, stranded or solid. NEC 2008 Table 310-16, *see 240.4(D)

Check out what this EE has to say about VD and power amp power supplies.

RE amp load
With stranded wire the jacketing or insulator, can allow for an increase in current carrying, over that of solid wire of the same guage. For ex. a #14 stranded THHN will carry the same as a #12 solid romex.

RE Python VX vs. Taipan helix A.
Well then, i suppose wire gauge isn't the end all be all in cabling.... huh?

A long time ago you could buy brand new a Camaro or a Mustang, outfitted about the same... 350cid in the Chevy and a 351 cid in the 'stang.

Both are V8's.... both felt differently too.

If the Taipan HA & the Python VX were the same cable they would sound the same. They don't. Elsewise only one of the cables would have been made, huh?

The VX actually supplies front end & spinning gear whose current draws are far less than the draw the Taipans see routinely.

One would think the larger gauge cable needed to be on the amps, not the front end. Right Well audio isn't always intuitive.

Sometimes, it's all about the infulence, or what the item brings to the table in it's inherent characteristics... not it's specs.

Let's not forget too, them magical beans, er, beads, in the VX.

I have moved them all around in all of my systems, and they work elsewhere. I just feel they work best for me in those spots & reasons, I mentioned. Hope that makes sense.