Originally Posted by AcuDefTechGuy
How much does it usually cost to install (retrofit) a 20A circuit?
FWIW, there's no retrofitting as you'll be running a separate circuit from the service box. As to costs, it's a bit of a wide target as to make sure it's all done to code, it's going depend on permit costs with the city or county. Next, it's going depend on if your service box is up to current code standards. The rub being, once your box is touched, the service will, by law, be required to be brought up to code and that can be two or three thousand dollars alone.
Right or wrong, assuming you don't have to upgrade your service box, it's going depend on attic or under house crawl space accessibility. The more difficult the access, the higher the price; this couple with the prevailing per/hr wage structure. In our case, where we're located, I'd fully expect, to have a separate 20 or 30 Amp service installed, to be charged between $500.00 0 $1,000.00 and we have "VERY" easy access and no need to upgrade our service box; house and wiring is ten years old.
In my opinion, at that price, considering it's all about entertainment, money well spent.