Have you ever gone out to the job and the electrician didn't wire you up a 220 outlet? It's bad enough to jump the main with alligator clips (like in this photo), but it's even worse when you have the sander running without its own breaker. If there is ever a problem with your sander or cord, the clips could over-heated and short out, creating a fire or causing personal injury to the machine operator. If those wires overheat, it will look like fireworks inside that electrical panel box. And one touch to the wires inside that box and you'll be thrown back about 7 feet.
As a professional floor technician, safety is important, and so is protecting the personal property of your client. I've heard about people shorting out the entire main box on a big project-that's expensive, plus you have to explain it to the authorities. In my area, you can be fined $10,000 by the electrical inspector for hooking up in the box like this.
When finding power for your big machine, remember this about a hookup like this in this box:
1 - It's unsafe
2 - It's illegal.
(For more on safe power hookup, read this article from HF.)
