Properties of relays
What you're looking for is called a contactor. An example of a contactor meeting your requirements can be found at Digikey, but any electronics distributor will have the sort of thing you need.

Be aware, though, that high-power relays need high-power coils in order to move the contacts quickly through a long throw to quench any arcs. The units I linked, for instance, need a 24VDC coil, but pull nearly 3 amps. And yes, that's about 70 watts of coil power.

They also are not cheap, and you should figure on a ballpark figure of 100 to 150 dollars.