I had a licensed electrician put 120V 20A outlets on the 240V circuits when he wired my shop. It was permitted work and the city required a licensed electrician which the contractor provided. I could have done a much better job. It was easier to fix the errors myself than to communicate the problem into a language in which I am not fluent. I contacted the city inspector. He said that unless someone is killed the city doesn’t pursue electrician for their mistakes. Seems to me that’s how accid are prevented.