run tt off home power

I have a 20A outlet on the outside of the garage next to the driveway. I only need a 15' extension cord to plug in the TT. The only things off that plug are the garage (nothing plugged in) & the porch/outside outlets (1 string of Xmas lights plugged in). With a Pup,
An HTT, a C, and now the TT I have always been able to run the AC.

I can run my A/C for about 30-45 minutes on a 15 amp circuit, no extension cord. Then the breaker trips thermally. The 15-30 adapter also gets pretty warm.

So you should do better with a 20, but the extension cord, even a 30 amp cord and additional connection resistance, is going to cost you some voltage. Try it, put in a voltage meter to see what happens to voltage inside RV when A/C is running. I don't like to see it below 108, not too much of a problem for me at home because I'm close to the transformer and get 130v at the garage outlet.

Watch all of your plugin connections, and the adaptor, for heating. If you have a problem, it will most likely be a socket or plug burning up. Especially if you have cheap 15 amp lamp-grade sockets on that 20 amp circuit.

There is only one proper way, and that's to run a dedicated 30 amp, 120 volt circuit to an outside 30 amp rv plug. Everything you would need is available from Lowes or Home Depot, and depending on the length of wire run to your outside wall, could be as cheap as $50 -$75 bucks. Thats less than a good 50 foot 10 guage extension cord and the adapters you'll need.
I did this myself, and my motorhome stays plugged in 24/7, and I don't have to worry about tripping a breaker either in the rv or the house.
Grumpy

For quite a while I ran the coach with a 75 foot extension cord with three 10 gauge conductors, plugged in a 20 amp outlet. It worked.
Then, I installed a 30 amp RV outlet on the side of the garage, connected to a 30 amp breaker in the box. The 50 foot extension cord that is now required is also three 10 gauge conductors!
I have run both air conditioners, no problems.

We have been able to run our AC on our coach using a 20AMP drop cord and adapter. Then there have been other times we couldn't...it was hotter when it kept shutting off so I'm not sure if that had anything to do with it.

We run our AC plugged into our garage, as we don't have AC in the house. This summer we really have enjoyed it. That being said on the day's that we were in the high 90's, we did pop the breaker once, when I was vacumming the trailer with the AC running. The chest freezer and our extra fridge are on the same circuit in the garage...or actually they were. We just re-wired the outside box to its own breaker, so right now the trailer has its own dedicated "plug", while in the driveway. When we move the trailer to the other side of the house...we are still deciding if we are going to give it its own dedicated circuit and if that is going to come from our garage or house.

The joys of having a garage that was a metal machine shop for 30 years, we have 3-phase 220 into our garage and lots of capacity to do a dedicated drop.

It's all a matter of what you want/need to do with the trailer. If you want to operate the same as you would at a c/g, you need a circuit of #10 wire from a 30 amp breaker ending in a 30 amp RV receptacle. A 20 amp circuit with #12 wire should allow you to run the A/C but very little else.

Regardless of what others have said/done, I would never attempt to run the A/C on a 15 amp/#14 circuit. Even if the breaker stays closed, the voltage drop will likely be too great and possibly damage the unit. You also will quite possibly overheat your house wiring for that circuit, damaging the conductor insulation.

To all of you naysayers, please note that I used the words 'likely' and 'possibly'. There are always exceptions, but I stand by this wording as a professional electrical engineer of 30+ years.

I had always thought that you could not run the air on anything less than the 30 amp because it was hard on it not getting enough electricity. I have been hooking mine up to the house for years but not using the air, if I can use it that will help a lot.
Another question, if you change the plug to a 30 amp you would have to change the wiring to a heavier gauge wire, right?

Yes you can run your camper on an extension cord from your house, but you are limited to the number of amps available for the circuit you're connected to. And that number also includes anything used inside the house.

We ran a 100 foot orange construction style extension cord from a 20 amp service to our 30 amp Springdale TT for years. It was fine for keeping the battery charged, to run a television and DVD player, even keep phones charged and such. It would run the air conditioner, but after some time, the extension cord would begin to get very very warm, an indicator it was time to shut the air conditioner off.

Eventually, I got 30 am extension cords for the camper (had 135 feet total), and the cord never got hot. But the breaker in the house did pop a few times. We learned to watch what was turned on.

When we got our new Outback (about a year ago now), I went through the effort to go ahead and install a 30 amp service in the garage. Now we have no problems with anything.

To answer your question? Yes you can run of an extension cord, but if the cord gets hot, you REALLY need to get a heavier cord! If you're going to run your camper, I strongly advise, bite the bullet and get a true 30 amp cord, long enough to reach your home to camper. You will not regret doing that.

Good luck! FYI, we sleep in the camper every night in our driveway. Hooked up the Tailgater (Dish satellite) and absolutely enjoy ourselves every day! You will too!

I do it all the time on a 15amp outlet. Everything that is propane/electric is on propane. Nothing on the same circuit in the house. Converter off and all powered appliances unplugged as a reminder. Guests educated on power management. Voltage drop, even with a "heavy" extension cord was unacceptable (hovering around 105) so I now use a regular 30amp RV cord and the voltage stays above 110. Use a plug in voltmeter and leave it on so you can monitor the changes. You should be good to go.