Re: Power Cords
I don't think that any of us are quite sure exactly what you mean. Does your RV have a typical RV power cord with a 30A plug at the end and loads inside for use of 30A of power by things like an air conditioner and microwave and such? If that is what you have, then when you need to use an extension cord, the best answer is to use a 30A rated extension cord. If you are connecting to a typical household 15A outlet like those in all homes, you will be limited to a maximum of 15A of power no matter what your RV has or what size that power cord is.
Where the cord size becomes critical is in the length of the total cord to RV's power distribution panel from that outlet. The longer the power cord and the greater the power demanded from it, the more the voltage will drop on the way. No power cord is free from resistance so it uses some of the supplied power just to get any current to the RV. The longer the power cord is, the larger in diameter it needs to be.