On Fri, 16 Aug 2013 05:58:27 +0000, David Lesher wrote:

Przemek Klosowski writes:

Lets say there is a 100' extension cord (with metal copper conductors)
energized by a live household 120V 60Hz outlet. Nothing is plugged
into the cord, and it's one without any indicator lights or ground
fault gimmicks. Said cord is dry, other than the typical indoor
humidity of a normal household garage.
...
The main loss will be through the AC current driving the cable
capacitance. There's also radiation losses but at 60Hz they are
negligible.

A capacitive load consumes no watts.

We agree violently---I said "The current in the cable itself is of course
non-dissipative". At the same time, driving that capacitance through the
power company and house wiring does carry losses. That's why we care
about the power factor: the wiring/distribution system losses cannot be
avoided but at least at Pf=1 something is doing work at the end of the
line, whereas at Pf=0 (the case of our extension cord) it's all for
naught.