Quote Originally Posted by Fursphere
If you run above that for a period of time, you will eventually trip the breaker as the wires overheat.
Actually, its worse than that. If you run it at 90% - 95% load for extended period of times, it'll cause the breaker to heat up, but it won't trip it.

Trips are caused by spikes in the load. If you ease into it, you can exceed load and burn up your breaker / panel at the time. It takes time, but it'll happen.

Best case - your break will burn up and cease to function, but won't start a fire.

Worst case - fire.
I am going to reiterate this warning. Don't push the limits of your breaker. It should ONLY kick in because of a short or if you are overdoing it. You need to be very careful and should NEVER EVER overload a breaker. They are there as a final failsafe - NOT as a "to let you know when you have over done things". And yes, it is possible to reach the limit where you are toeing the line between it not breaking and breaking but you are going to be playing, perhaps literally, with fire. Don't ever do that. Install another dedicated line.