There have been several posts recently regarding ESC's failing and In some cases catching fire. I have had some experience of this at my own club's sailing site. The most recent Involved a twin prop model where only one of the esc's burnt out. The burnt one was set to turn the prop In the correct direction by setting the Tx channel to reverse.

Most ESC's have a forward current rating (say 50 amp) and a reverse current rating (say 20 amp).
You need to ensure that when you connect up your radio gear your ESC control channel on the transmitter Is set to normal. If the motor Is turning the prop In the wrong direction then (after disconnecting the power) reverse the two wires from the ESC to the motor.
Most modern transmitters have a simple switch to reverse the direction of servo's and ESC's. Changing this to reverse will make the model run In the correct direction but the ESC will now be limited to Its lower (or less) reverse current!

As a rule of thumb I normally use an ESC with double the maximum current I expect my motor to use - the max ratings are sometimes optimistic and often not sustainable over long periods.
As always do remember to put an In line fuse ( less than the ESC max current) In the battery power lead.
dave