Originally Posted by laurajean
Depending on the size of your air-conditioner along with temps and such, it can easily average 15 amps. Your water heater element is 12 amps when it's energized at 120 volts. The fridge might average 5-8 amps. You can see this is over 30 amps.....and this doesn't count a few more amps that your converter is using to power the lights and other 12 volt stuff in your RV......or a television or anything else plugged into outlets.
Also, campgrounds are famous for having low voltage, since there are so many campers on the same lines. As voltage goes lower, then things like motors draw more amps...so your A/C could be using more than 15 amps.
You might can just turn off the water heater on electric if this keeps occurring, and be good to go when you have the air-conditioner going. If it still trips after that, then you may have another problem......but it sounds like maybe you just overloaded the 30 amp.
One of my camping buddies and I both have 15000 A/C's, and we have run into this problem down here in the deep south when it get's hot. Using the 3 things you mention trips our 30 amps on occasion too. I've gotten to the point where I just use the water heater on propane in the summer, and live on.