Hi Zaikesman,
Caelin's recommendation of no shorter than a 1 meter length has to do as much with practicality than anything else. Although shorther than three feet essentially just adds connecting points and puts you kissing distance from your Romex--so what's the point of a nice PC, then?
Often times the IEC of a component is inverted (upside down). If you say, order a two foot length measuring fom IEC to the wall. You get the cord, then realize than you have to turn or invert it to match the outlet in the wall, guess what, it's too short. That, and the loss of resale value and in our opinion, a performance loss, are the reasons I warn customers that want a one-meter or shorter power cord.
Regarding Guido's reference to a 30 foot power cord we made: Astoria Studios (Pink Floyd) requested a 6ft Anaconda to try with their Studer Master Deck. We supplied a 6ft length for eval. hey were skeptical that it would make _any_ difference because all the power supplies of their electronics were heavily modified by Tim Diparavacini.
They had to wheel the Studer deck across the floor for the eval because the 6ft length of the power cord was far too short. Based on listening results, they ordered a 30 foot Anaconda to allow the distance required for the Studer's normal place on the floor.
Soon after recieving the 30 footer (we took pics before shipping as its the longest we've made), the studio manager called us to ask what the new, incredible model was as it was light years better than what we had sent for test. We explained why the difference existed and they understood. Since then, they have been our greatest protagonists in the pro realm and ordered more than $150k worth of product. Anectodal, sure. However, in such a high rez application, it speaks loudly to our point. Wont be true of all PC's likely, but it is with ours.
YMMV