Water Heaters - water heater keeps switching the breaker

My water heater keeps switching the breaker off. It just started this week. The first time I noticed I didn't have any hot water was after my husband had showered and left for work and I got up to get my shower and there was no hot water. I checked the breaker and it was off, so I switched it on. Everyday it's the same thing. It seems after the water tank empties out and it has to refill and reheat it cuts off. What could be the problem?

A shorted element in the heater seems most likely. If it has 2 elements, I believe they come on at different times as the water is used. I don't know the exact cycle, I've always had gas heaters.

One of the experts will be able to describe the sequence.

Normally, I would replace both at the same time while all the tools are ready.

Also, if you post the model and serial numbers, we can determine how old the unit is and give more accurate advice.

if you reset the breaker a had water for a shower then the settings of the 2 heaters might be too close,so when the hot water is replaced with cold they both come on tripping the breaker.simple thing your husband can do is knock the breaker down and check the electrical connections from the CB right into the heater.especially the wire nuts in the top plate that feed the heater.

Sequence: cold tank-upper element comes on first. When it's happy it switches off the upper element and simutaneously switches over to the bottom element thermostat which takes over and heats with the bottom element until it's [the thermostat] happy. During day to day operation the lower element and thermostat are the workhorses while the upper element and thermostat come into play when there is a lot of hot water being used. You probably have a grounded or shorted upper element. Shut off the breaker, take off the cover of the upper element and stat, look for burned wires, etc. If the wires are ok, remove the wires from the element and ohm test it for resistance and grounds. The elements are in the neighborhood of 4500 watts which means the resistance of a good element would be apprx. 13 ohms. [R=240 x240/4500] Now, someone is going to figure out that is apprx 19 amps and ask why do you use a 30 amp breaker? Answer- NEC considers a household water heater to be a non-interrmittent load [meaning it could be on for 3 hours+ making it a constant load by definition]. A constant load has to have the wires sized for 125% of the amp draw. 1.25 x 19 = 23.75 amps. Well, ya can't use a #12 wire for that so you go to the next size up which is #10. #10 is good for 30 amps. One could use a 25 amp breaker and be ok but a 30 amp is standard practice. I'm thinking there is a special provision that allows the 30 over the 25 where a 25 was once mandated but I'll have to look that up.