#1, What's a proper install? Did you have a licensed plumber install it?
Any water heater I've seen has right on the box and in the manual do not return to point of purchase, to call a 1-800 # first.
Who and how are you are you checking for voltage?
Both elements do not get power at the same time.
100 % sure the tank was full and someone had opened up a hot faucet to make sure there was flow before hitting the breaker.
In less then a min. the element will be melted of there's not enough water in the tank.