What makes a 20A IEC rated for 20 amps?

Ozzy. 99 times out of 100 manufacturers put 20A IEC on their piece for looks, or in belief of a better connection. Few items will ever pull more than 15A and if they do you need a 20A circuit all the way to the breaker

ARC for example use 20A IEC on all of their Ref pre amps but they are all low current draw.  So in this case you could buy an AQ Dragon power cord source version, which is only 16AWG but can be supplied with 20A IEC for use with such a pre amp.

I changed the 20 amp IEC on my Furman REF 20 to a Furutech 15 amp IEC, no problem at all.The blades of the Furutech are thick and certainly able to carry the current the screw lugs on the Furutech IEC also fit 10 gauge wires...One thing to remember, some Furutech IEC are NOW TOO LARGE to fit the old IEC holes. The old model Furtech IEC fits all IEC holes.'                  
"" The new Furutech FI-06 IEC inlet is the successor to Furutech's excellent FI-10 series. The primary difference relates to the upgrade from high conductivity phosphor bronze to pure, solid copper used in the FI-06. Please note that the size of the FI-06 is larger than the FI-10, ""     (so you have to enlarge the hole)    
The Fl-10 is still available from some sellers.

Elizabeth,

Thanks, I agree.
About the change in size on the Furutech, I found this out the hard way...

ozzy

After talking with a few Audio friends, we concur that probably the reason for the 20A IEC on the back of some component is to ensure that whatever power cord is plugged into it can handle 20 amps and consists of 10-12ga wire.
That is; all premade 20 amp power cords that I know of do come with substantial internal wiring.

Of course anyone can put a 20A connector on any cable regardless if it has 10-12 ga wire inside. Then, there are the 20/15A adapters we use, who knows what type of gauge is used with them.

ozzy

My new Inakustik AC-3500P power conditioner that is rated at 15A comes equipped with an IEC inlet rated at 20A. According to the dealer, that inlet is better at supporting cleaner power surges than an IEC inlet rated at 15A.