My men are on a job when they notice the deadfront had been removed from our temporary panel. Apparently the foam insulator needed 220 and instead of coming to us installed his own breaker and hardwired his machine into that breaker and did not replace the cover, which is difficult to do obviously with a cord wired directly into the breaker. My guy turned the breaker off, removed the wire, and closed the panel back up. The foam guy start yelling about how he does this on all the jobs and its never been a problem. Now he is claiming that we burned his equipment up when we unlanded the wires. My most trusted foreman watched as our guy turned the breaker off and unhooked the wires. Question #1 : Am I justified in telling the foam guy to take a hike, stay out of our panel. Question #2 Even if by some divine intervention we did burn his equipment up(which I would like him to explain how we did other than by single phasing it) should I really care?