Why Does My Water Heater Keep Tripping the Breaker? Causes and What to Do

A breaker is a safety device. It trips because it saw more current than the circuit should carry, or a short. Resetting it over and over does not fix that, and Rheem's manual tells owners not to attempt repairs to wiring, thermostats or heating elements themselves (Rheem manual).

Graphic: summary of this guide, made by our team from the cited sources.

First: is it the breaker or the red reset button?

These two get mixed up all the time, and they point to different problems.

What tripped	Where it is	What it means
Circuit breaker	Your main electrical panel, usually a double breaker labeled "water heater"	Too much current or a short somewhere on the circuit or inside the heater
Red reset button (ECO, high limit)	Behind the upper access panel on the heater	The water got too hot. State's handbook says the ECO shuts off the elements if the top of the tank reaches 180°F (State service handbook)

If only the red button tripped, see Rheem's instructions: power off first, and the cause of the overheating has to be found by a qualified technician before the heater goes back in service (Rheem manual). The rest of this page is about the panel breaker.

The usual causes, most likely first

1. A grounded or shorted heating element

A heating element has a resistance wire inside an insulated metal sheath. The insulation keeps current away from the water and the tank. When the sheath cracks or the insulation breaks down, current can reach the tank, and the breaker trips. State's service handbook gives a continuity test between each element terminal and the tank, and says an element that shows continuity is grounded and must be replaced (State service handbook).

Clues that point here:

• The breaker holds for a while, then trips when the heater starts heating (for example, after a shower or overnight).
• The heater is older, or you have hard water and have never drained it.

2. A "dry fired" upper element (new installs and after draining)

If the power comes on before the tank is completely full, the upper element heats in air and burns out. A.O. Smith calls this a common installation mistake and tells installers to run a hot faucet at full flow for three minutes or longer before connecting power (A.O. Smith instructions). A burned element can fail open (no heat) or fail shorted (tripped breaker).

If the trips started right after the heater was installed, drained or flushed, tell the installer. A.O. Smith notes a dry-fired element is an installation error not covered by its warranty (A.O. Smith instructions).

3. Loose, burned or damaged wiring

Loose connections heat up and can arc. Look (do not touch) at the junction box on top of the heater and the cable going into it. Scorch marks, melted insulation, a burning smell or a warm cover are reasons to keep the power off and call a licensed electrician.

4. A breaker or wire that does not match the heater

The heater's rating plate lists its voltage and wattage. Whirlpool notes most residential electric units run on 240 volts, with some at 120 volts (Whirlpool). The breaker and wire must suit that rating:

• State's handbook says breakers should be sized at least 125% of the heater's expected amperage, and works the example of a 4,500-watt element at 240 volts drawing 18.75 amps (State service handbook).
• Rheem's sizing table lists a 25-amp breaker and 10 AWG copper wire for a 4,500-watt heater at 240 volts (Rheem manual).

A breaker that was fine for an old heater may be too small for a replacement with bigger elements. Breakers also wear out. Both are jobs for a licensed electrician.

5. A heater wired to run both elements at once

Most two-element tank heaters are wired so only one element heats at a time. State's handbook says the elements do not run together unless the heater was ordered with simultaneous wiring, and if they do, the amp draw doubles (State service handbook). A stuck thermostat or a wiring mistake that lets both run can overload a breaker sized for one.

6. Water where it should not be

A leak from the tank, the relief valve or a fitting above the heater can drip into the electrical compartment. If you see water or rust inside the access panel or on the floor, keep the power off. Rheem says a heater that has been through a flood should not be operated again until a qualified technician has checked it (Rheem manual).

What you can safely check yourself

Do these with the breaker off. Nothing here involves touching wires.

1. Note the pattern. Does it trip instantly when you flip the breaker on, or after minutes or hours? Instant trips point to a dead short (wiring or a shorted element). Delayed trips point to an element that fails once it heats, or an overloaded circuit.
2. Look for water. Check the floor, the top of the tank, and the pipes and relief valve above it.
3. Look at the junction box on top of the heater for scorch marks or melted insulation. Smell for burning.
4. Read the rating plate. Write down the voltage and wattage, and the size printed on the breaker handle. That gives the electrician a head start.
5. Think about recent work. New heater, drained tank, new element, panel work? Mention it.

Reset the breaker once at most. If it trips again, leave it off.

What a technician will do

Expect the technician to test each element for resistance and for a short to the tank, check the thermostats, tighten or replace damaged wiring, and confirm the breaker and wire match the rating plate. A.O. Smith's troubleshooting section, for example, has the technician measure each element and replace any that read outside the expected range (A.O. Smith instructions). Element and thermostat swaps are common repairs. A leaking tank is not repairable and means replacement.

When to stop and call right away

• You see sparks, scorch marks or melted wire, or smell burning.
• There is water in the electrical compartment or around the base.
• The breaker trips instantly every time.
• The breaker panel itself feels warm or other circuits are acting up.

Call a licensed electrician for panel, breaker and wiring problems, and a licensed plumber or the manufacturer's service line for the heater itself.

Gas water heaters

A gas water heater does not have heating elements, so it rarely trips a breaker. Some models have an electric igniter or a power vent fan on a circuit; if that breaker trips, the fault is in that component. If you ever smell gas, leave the house and call your gas utility from outside.