Could be a lot of things that happened in the last 10 yrs. Lets try to localize the problem.
Turn off TT breakers then plug into the same house outlet as you normally have done. See if its the 30 amp TT cord. Then just try a different house outlet to be sure its not the house outlet that has developed a short.
If the house does not trip, turn on one TT breaker at a time, see which line it is and go from there. At least you will know which line it is causing the problem.
If your battery is very low and your converter is running at full trying to re-charge it , maybe its possible that your TT is drawing more than 20 amps while the fridge is on 110v.
You might try to fully charge the battery on a separate charger while not hooked up to the TT. Once that's done, hook the battery back up to the TT and plug in the TT to 110v, see what happens.
If you have an elec. water heater, shut it off.