15 amp vs 20 amp Power Cords

Outside of the fact that both femal connectors are shapped differently what are the differences since both originate from the same source?
For audiophile aftermarket power cords. almost NOTHING.
True a few of the designated 15 amp cords may not be able to carry as much current as some others, but in general all the aftermarket power cords are robust enough for 20 amps.
(With one exception: Mapleshade powercords are really totally too fragile for any use other than small electronics, Same thing for their power distribution devices IMO.. and a few other bizarre designs which violate all the codes anyway... LOL )

I changed the 20 amp inlet to my Furman REF20i to a 15 amp style inlet IEC so i could use a Pangea power cord.
The IEC (Furman) I used has rooom in the wire attachment point inside the conditioner for ten gauge wiring. Which is good enough for my concerns of amperage and such.

There are charts for ampacity and usage just Google them.
12 gauge is all you need for a cord to carry 20 amps.
My Pangea are 7 gauge.
So if I understand you correctly a device that uses the 20 amp style connector (C19) should be a minimum of 12 guage or larger?