In the State I live (MA) a homeowner is allowed to do their own wiring, they are supposed to pull a permit and get inspections but that's another story.
Plumbing on the other hand in this state has no such leniency, you must be licensed to do plumbing work, go figure.
As a guy that does service calls I like that HD has a lot of electric supplies, some of these stores are open 24 hrs.
We needed thousands of feet or 12 and 14 awg on a Sunday repair call, stops at couple of these stores got us what we needed.
Bob