I have been doing stuff like this for years, up to 480V 3 phase, and 0000ga and bigger.
I happen to be an Electrical Engineer, designed and built TV facilities for years.
But at the moment had some eye issues, so I figured I would call Milestone Electric
("They'll fix it in a flash" is their jingle) in the Dallas - Ft. Worth area. So two guys
come out, see an old man with a beard, cane, and an eye patch, and figure they have
one on the hook. $1250 to install my 40 amp breaker, run 4 feet of wire to 4x4
box and install my connector, or $2500 to install the Tesla charger adapter and about
10 feet of conduit. "But we can't use your breaker, box or connector, we can't use that
Home Depot c__p". (I bought the stuff from the local electrical supply house
by the way). Then went on about their free full home evaluation, and then the kicker -
"Since this house is about 25 years old, you know you need to replace the panel and
all the breakers. Everybody knows they only last 15-20 years. Now we can do that
after the whole house inspection and - ". He was cut short as I told him to pick up
his gear, put a light coat of oil on it, insert it in the first convenient orifice that came
to hand while looking out for the square corners and getting off my property. I refused to pay
their $special$ $79 estimate visit, the fraudulent S O Bs.
My real estate lady sent her handyman around, $100 cash. Done in an hour.
Later had a beer with a local bonded licensed electrician. He would have charged me $250
and permitted it if I could let him do it when he had a couple of hours on a light day.
200-300 bucks for a licensed electrician's time is not out of bounds. They have expenses to pay,
too.
Not all are ganefs like Milestone.