...thanks, but this is why we have questions to try to help you... this is the first time you've stated that your own RV is only designed for 20amps of power - your original post made it sound as if your friend's house outlet was a 20amp outlet.
so, if you are plugging into your friend's outlet, which is more than likely a shared circuit on a 15amp household breaker, then you have even less AMPS to use, especially if that circuit is shared within the house with other outlets which may have items, devices, lights, appliances, etc., being used. Your RV is now 'sharing' these amps with the house.
maybe you can take a few pictures of your RV's electrical breaker panel, and the outlet you are plugging into, and add them to your reply post with the 'go advanced' button below, and we can help even more...
: )
Electrical within RVs is sometimes one of the most aggravating 'features', but hang in there!
__________________
|