@ryder - as someone above posted - the Gauge of the power cable is not the full story
- The wire in the wall is genrally solid wire
- it is capable of delivernig better/cleaner power than a normal power cable
- Power cables generally use a stranded wire to maintain flexibility
- stranded wire cannot carry as much current as a solid wire
Some power cables use a solid wire or 3-4 solid insulatied wires
- these generally perform better than most other power cables.
But that is only a small part of the story - take a look at this thread for a more detailed explanation
Hope that helps - Steve