In the company I worked at used a 240 V masonry saw we used to wire our own breaker in the panel. So 1 day my boss owner of company sales he will install breaker. So to keep the saw head from jumping you put one hand on the metal handle and turn saw on with other hand. WACK hand was thrown off saw and twitching. One of the very few times I’ve ever went nuclear on a boss green is ground not black. Here’s your sign