Do I need 10 gauge power cord if I have 10 gauge from panel?

I should have added that every circuit in my home is 20 amp. It was built that way and not something I did as we bought it from the original owners. 

FWIW I built my own power cables using Furutech bulk cable and connectors. You can buy what awg you want as well as shielding. I made mine custom length to each component. I bought cable covering from Amazon and some shrink tubing for the ends. It was fun project. Cost was around $170 per cable. You can buy less expensive connectors if you wish.