Contractors....HVAC ductwork question

Steve, at least you are thinking. You probably would not believe the "home improvements" I"ve seen over the years

One of the potentially dangerous was showing up to finish an AC install in time to see one of our crew "wondering" about a sawzall. He'd plugged it into an extension cord the homeowner left in the basement and nearly burned up the tool

Turns out the homeowner had a 120V cord he'd cut off and hard-wired to a 240V breaker pair to operate a window mount AC unit!!!!! Which also means he'd taken the trouble to chop off the AC plug on the windowbanger and change it from a 240 to a 120V connector!!!

The homeowner was unhappy with me when he stopped by and found his cord had been yanked out of the box. I told him "I'd be happy" to get the inspector over here if he wanted. I also made it clear that, above and beyond the job bid, he would probably be paying for a sawzall.

What the heck was the home owner thinking?? Up here our residential "window shakers" as we call them are 120v. BUT I gotta say that worker shoulda been checking both ends before pluggin into it. Bet he does that now! LOLCeiling in the basement is low, and we are restricted obviously with the ceiling joist height. The current rect duct(heat) hangs lower than the joists, so if I could once Im home be able to "raise" the ceiling if possible.ThanksSteve