Can anyone tell me where to find code info on sizing appliance cords? I can not seem to find anything regarding dishwashers in particular. Seems most electrical appliances come with cords rated for less than a 15 or 20 amp circuit. I would like a definitive answer on installing a cord on a dishwasher. Thanks....Scott

Some of the info can be found in 422-16(b)(2). Length 3' to 4' from grounding type plug on cord to rear of appliance.
Then check out 240-4 for wire size and OC protection relative to what the nameplate of your dishwasher says. Probably SP type cord (table 400-4) 14 or 12 AWG. You really need to check out the local code because this is a subject frequently visited and amended by state and local authorities.

In general, ampacities of most common types of flexible cord can be found in Table 400-5(A) You can usually use Column B, but check out the small print at the bottom of the table.

Here's an example, 2 burner hot plate draws 20 amps, needs to be on a 30 amp breaker since it will be on all day. Branch circuit conductors are #10, but the cord only needs to be a maximum of #12.