[Al Skierkiewicz]

Yes there can be a huge difference in AC vs DC for circuit breakers. The type you link to is designed for three phase AC power. The trip mechanism is an AC solenoid that pulls on a release tab when the current exceeds 7 amps. The breakers are linked so that if the current on one exceeds the trip, all three poles break at the same time. The 250 VAC refers to the safe operating distance when the breaker is open. 250 volts AC will not arc across the distance between the contacts. This breaker would work as a switch on DC but would not act as circuit protection. Snap action breakers of the type we use are rarely seen in the same applications as the breaker you linked to. Often these breakers are used in environments where the temperature is high during operation particularly if stacked next other breakers in the same panel. Some breakers designs will use both snap action and solenoid release to insure circuit breaks over a wide variety of conditions. Safety is a major concern when using these devices.