My electric furnace keeps tripping the breaker , it will run for about five or ten minutes then trips.

You need to use rated breaker and did you find a fault for why the breaker shorted?

Electric furnace I assume- check with amp meter, if amps are below listed on breaker, replace the breaker, [check both the breakers in the furnace and in the house pannel, even if only one is tripping right now, the other(s) may start doing the same thing after you eliminate the weakest link- don't be surprised!] electric furnaces are notorius for "eating" breakers- they overheat the breakers for years then the breakers get weak and trip too easilly... if gas, post more info and I'll try to help further.

1) You got a FIRE truck coming.

2) Wire is too small.
Problem is NOT circuit breaker.

3) Both 240Volt appliances on same breaker is a hazard, especially if space available in 200 amp service panel for more breakers.

4) Usually each 240V appliance has separate breaker.

5) Circuit breaker trips because of High heat on the wire.
If wire gets hot, it will start a fire inside the wall.

Electric code requires wire-size match breaker-size.

6) If you put larger amp breaker on same wire that is getting hot, then wire will get hotter.
Result: FIRE truck middle of night with folks jumping out window in glass-cut bare run across yard.

7) Each appliance has volts and watt rating on label.
EVERY appliance has label.

8) For example stove might be rated 8000 watts and 240Volt.
8000 watts divided by 240 volts = 33.3 amps
Stove would require 40 amp breaker and 8 gauge wire.

9) How to figure it out:
http://waterheatertimer.org/Color-codewire.html
http://waterheatertimer.org/How-to-install-a-subpanel.html

10) Do same calculation for new furnace.
12000 watt furnace divided by 240 volts = 50 amps.
Use 60 amp breaker and 6 gauge wire.

11) Summary: fixya wants you to be safe, and buy stuff showing in the ads.
Use a bigger breaker ONLY when bigger wire is also installed.
Call furnace installer, the installer should know to check safe wiring before installing.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Yes they get weak over time.
The main will trip when it senses heat.
Use hand to feel if main breaker is getting hot.
http://waterheatertimer.org/Troubleshoot-household-electricity.html#stress
http://waterheatertimer.org/How-to-replace-circuit-breaker.html

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Disconnect the black power wire where it is connected to the furnace with breaker off. Put a wire nut on it and then turn the breaker on. If it continues to trip, the problem is not the furnace and you will have to trace the power wire back to the breaker box to find problem. Next, disconnect the black wire from the breaker (with breaker off) and then snap breaker on. If it trips, bad breaker. If the furnace was disconnected and breaker did not trip, you have a short either on the P C Board or the transformer.

When does it trip? Do the burners light first? How many minutes from "ON" to trip?

First HACR is heating, air conditioning,refrigeration. So in other words you could use it on an electric furnace or air conditioning.
IS this the main breaker for the panel? or for and electric furnace. I'm assuming its for the furnace, perhaps back up heat for heat pump. See if there is another disconenct on the furnace, turn it off and see if the breaker resets. IF so you have a short or overload in the furnace.
If' it IS the main for the panel, turn off all the other breakers in the panel, and try to reset the breaker. If that works, turn the other breakers back on one at a time. IF it "POPS" then it is tripping. Don't keep resetting, find the problem.

it is normal for a breaker that is run right on the edge (50 amp and your furnance to use 45) to get weak after a while . the first thing you should do is change the breaker with the same type and amp rateing . it should take care if it

Furnace. To confirm use an Ampprobe or other brand ampmeter and see how much current is being drawn. If it is more that 80% of the breaker rating, it si for sure the Furnace.

Whats the amp breaker? Is this for the inside unit or the outside condenser? If the inside and gas heat you have a bad fan motor, If its an electric furnace , the same, but if its the outside unit, the fan could be going bad, locking up and the compressor still runs and pulls high ampsand tripps breaker or the compressor is just pulling too many amps due to plugged coils with dirt , grass or weeds blocking airflow.([email protected])