[chris vickery]

It is the inrush current that trips the breaker.
If you device is hovering around 16A a 15A breaker may or may not hold it. A better choice is to use a 20A circuit.
As it is not being used continuously at the 16A level, not really a concern.
Now that being said, as in the above post, placing a device such as the plasma cutter on a 50A circuit is just plain dangerous. Upsizing the breaker for a device meant to run 30A is a fire waiting to happen or at the minimum, potential damage to occur in your equipment during an overload situation