I want to run 75C wire. Can I overcome 60C receptacle ratings with a pigtail?
If you use a j box with terminals rated at 75 you can use the higher 75deg table or even 90 for the main run then the last few feet with the larger wire at the 60 deg table we do this using the 90 deg table running large +500mcm for hundreds of feet then the 75 degree temp for the last 10 feet or so at both ends same thing works for 60 degree table.