The most likely culprit is the immersion element. After a few years these elements crack and water gets in. The current from the heating part of the element infiltrates to the outer jacket of the element. This causes a higher than normal current flow. This will continue to get worse and finally you will end up with a short circuit where the breaker will trip instantaneously when turned on. The good news is that these elements can be replaced. The element will unscrew out of the tank and the exact wattage replacement can be screwed in. Remember to use pipe dope on the treads when reinserting the new element other wise it will leak from the connection point.
Reconnect the electrical connections and it will be good to go.
If it's a new water heater, the breaker may be too low of an amperage rating. However before changing, make sure your wiring is large enough to handle the required breaker current rating. If it's a water heater that has been in use and suddenly started kicking the breaker..........(1) check to make sure other devices haven't been added to the circuit to which the water heater is connected. This could be causing an overload on the circuit. (2) If there are no other devices connected to the water heater circuit, then you probably have an internal "hot" wire that is going to ground.
One thing to check is the thermo coupler. if that's the problem the heater is not sensing the correct temp and will shut off. pretty cheap and easy to change
There is a problem with one of the heating elements
Somebody must have wired it incorrectly.
Because hot water heater breaker has tripped, or hot water heater has failed.
If the tub is not getting hot water the issue is probably with the hot water heater. The hot water heater may have tripped a breaker or the pilot light went out.
turn off your water
Only if the hot water breaker is turned off.
yes, the breaker just controls the heating elements
YES!!
A stove is a two pole 50, and hot water heater i would recommend the same.
The wattage of the water tank is needed to size the breaker and the wire to feed the tank.
There is no way of telling from here. It will be a double breaker, most boxes will have 3 doubles. One for the stove, one for the AC and one for the water heater. Process of elimination should tell you which is for the heater.
no as it will burn out the element
Yes install it on the cold water line as close to the heater as possible.
The best way to determine which circuit breaker is for the water heater is with a voltage meter, It is suppose to be only one circuit breaker, but in a faulty application it could be two breakers