It could be as simple as a loose wire. Or it could be something as complicated as a water leak on the wiring that is shorting out the fuses. You can blow a fuse if the t-stat or temperature thermostat is bad too, causing it to draw too much current before getting things too hot.Click to see full answer. Then, why does my water heater breaker keep tripping? Reasons Your Water Heater Is Tripping the Breaker The problem could be: The breaker may be worn out and trip. A wire also may be loose in the electrical panel, causing a short circuit. Your thermostat – If your thermostat goes bad, it can draw more electricity than the circuit can handle, causing the breaker to trip. does a hot water heater have a fuse? The heater is usually fused in the main electrical panel but some electric water heaters may be fed from a separate fuse or circuit breaker box. If the fuse is blown or breaker is tripped, replace the fuse or re-set the circuit breaker. Likewise, what size fuses for hot water tank? The amp rating of the fuses will depend on the wire size that is feeding the water heater. Many cases a standard size water heater will have #10 wire and 30 amp fuses. The circuit breaker should have a rating listed on it some place.Is it dangerous if circuit breaker keeps tripping?Repeated circuit breaker tripping caused by general wear and tear on the circuit breaker is usually due to one of the following issues: Short Circuit: A short circuit is common, but potentially dangerous. The circuit breaker automatically shuts off in cases like these to prevent an electrical fire.