Power Cables - 15amp or 20amp

Well, there's a LOT of mixing going on, as many manufacturers want to ensure that 20a PCs still can be used in customers' preexisting 15a 14AWG house lines!
The difference between 15a and 20a best quality AC males is simply the geometry of one spade, in order to assure use of the matching 20a outlet. Actual current-handling is usually the same, as the contact sets are identical in better quality plugs and connectors.
At the "IEC component" end it's completely different, as noted above. MOST 15a connectors have lighter weight contacts, as would be expected.
Here's a matrix that I follow when assembling or manufacturing my PCKits for folks:

Component IEC House Wall Outlet PC Male AC

15a 15a 15a
15a 20a 15a & 20a fit
20a 15a (don't do it!) 20a (won't fit)
20a 20a 20a only!

Using a 20a male AC on a big amp that still uses a 15a IEC is what I usually do, just to ensure that the customer uses a 20a line. Some guys have swapped these out for 15a male AC plugs to allow using these big amps on 14AWG 15a circuits...but that's a real compromise. Otherwise the matrix is pretty self-explanatory. Cheers.
ErnieM

Dear Readster,

The 15amp IEC has (3) vertical blades

The 20amp IEC will have (3) horizonal blades

Square hole - Round peg situation... (for your protection)

15amp Male/Female must be used with together and 20amp Male/Female must be used together. They cannot mix.

If you have any futher questions, we have lots of photos on our web site which you can refer to or drop me an email.
Dan

Krell man is right. A 15amp power cord will not fit into the socket of a 20 amp plug. The two are shaped differently. Make sure you get what you need.

Yes it matters. Most will be 15 Amp. However, the Shunyata Hydra-8 and 6 power conditioners require 20 Amp. The normal ones that you see are 15 Amp. The 20 Amp connector looks different.