I have a travel trailer and have bought a generator that needs to be grounded. If i am at a park site, putting the grounding rod in soil is possible, but on road, i may park at a parking lot to take a rest. What is the easiest way to ground the generator on asphalt? Or concrete? I was thinking about getting a 1/2" thick copper plate, about 4" X 8" and attaching the ground cable to it, the sliding the plate under my tires to hold the plate down firmly to the ground. Will that give me the ground i need for the generator? My generator is 6250 watts.