Booster, I am not referring to the TrippLite internal transfer switch but rather the in and out 120 volt connections on the inverter. Please see the picture, that IEC connector is rated at 10 amps continuous and the wire in the 3 wire cords is 3/14 AWG I think.
On AC circuits for 15 amps AC are rated for 14ga copper wire in all conditions except long cable lengths that would get too much voltage drop.
The rating on the output plugs in the boxes is after the Tripplite, and if yours is like the current literature there would be two output breakers on the unit rated at 6 and 8 amps so a 10 amp outlet would not be overloaded.
As mentioned earlier, the Roadtrek system is not typical because of how they do the "inverter" outlets that are usually kitchen, audio and maybe one other.
Shore power comes into the van and goes to the breaker box. The breaker box then feeds all the outlets except the three above. The power for those three goes through the Tripplite and right or wrong they may be limiting the output of those outlets. If they combined the outputs, you would have 14 amps, if they didn't you would probably get 8 or 6 depending which breaker. The Tripplite is a small unit that charges at 45 amps max and has 750watt modified sine wave inverter so they count on the entire unit taking no more than 15 amps of 110v AC and then the split off the charger allotment. The breaker that feeds it from the panel is 15 amps. It sorta kinda makes since to limit to the same output on shore power as max output on inverter, but also not really unless the transfer switch is too small, and that is likely in a unit of that size.
The 750 watt modified sine wave inverter is getting pretty out of date as it will not run a lot of current electronics or appliances because of the modified sine wave.
If you want to run a 1500 watt heater or appliance, obviously it has to be on shore power or generator. To do that you probably need to just plug into a "non inverter" outlet which are all them except the ones mentioned above. Extension cord would work, and rewiring the kitchen outlet isn't terribly difficult, I have done that in the past. All you do is run a cable down from the microwave outlet above it and disconnect/cap the original cable to it.
All the above is why lots of us have ditched the Tripplite. Our van has been modified to a much larger inverter/charger and wiring changed so all outlets can run on inverter and shore power through the unit. They are are at rated power with no limiting because the Transfer switch in the inverter charger is large enough to run 30 amps.
