If I run my Thermal Dynamics Cutmaster A60 on its highest setting it will occasionally trip the breaker. I discovered this circuit has a 30 AMP breaker on it, which was always fine for my welder or Japanese made plasma cutter. In looking at the breaker panel it is fully populated, and about 20 years old. I have had problems getting breakers for it before, and had to buy used ones on eBay

Deciding on a new panel with some expansion for extra circuits, I just bought a larger breaker panel (12 breakers instead of 8), and enough cable to bring a new feed from my main panel that is attached to a pole in my side pasture. In that panel I have a 200AMP feed for our mother-in-law apartment and a 60 AMP feed that did all my workshop/barn (a different electricity pole and meter supply another 200AMP circuit for the main ranch). I had planned to change this feed to the workshop/barn to 100 AMP. I read my manual for the Cutmaster and it says to provide a 6 AWG cable with a 100 AMP fuse. Can this be right? I'm fairly sure the socket/plug is rated for 50 AMP, so 100 AMP seems very high. I don't want to overrate the breaker and lose any protection it offers.
What AMP circuit do you run your plasma cutter on?
BTW (this is in the US and I'm using 220V single phase.)