Don Y writes:
On 1/25/2016 2:14 PM, FrozenNorth wrote:

The breaker/fuse is sized to the wiring/plugs, not what is plugged into it,
simple and end of story.

No. Run a 16AWG extension cord -- better yet, daisy chain 5 or 6 of
them together -- then throw a 15A resistive load on the end and
see what happens. (hint: 15A breaker won't trip) Do the same with
an inductive/reactive load.


It's perfectly acceptable to use a larger gauge of conductor,
than the baseline for a given ampacity. In fact, the code
tables for ampacity vs. gauge note that for longer runs, you
must increase the gauge to avoid voltage drop due to resistive
loading of the conductor.

NEMA 5-20R are specifically designed to allow a NEMA 5-15P, so
using 5-15P on your extention cord not only conforms to the
NEC recommendations, but is a logical move as well if have
a desire to use the same cord with a NEMA 5-15R.