Quick answer: Electric water heaters typically fail to heat because of a tripped breaker, a tripped high-temperature limit switch, a failed heating element, or a failed thermostat. You can safely check the breaker. Element and thermostat testing involves exposed 240-volt connections and should be done by a qualified professional.
A cold shower is usually the first sign. The cause is often electrical.
How an electric water heater works
Most residential electric water heaters run on a dedicated 240-volt circuit and use two heating elements, an upper and a lower, each controlled by a thermostat. A high-temperature limit switch shuts off power if the water overheats.
Safe checks
- Breaker: Find the water heater breaker, usually a double-pole breaker. If tripped, reset it once. If it trips again, leave it off and call for service.
- Disconnect: Some installations have a separate disconnect near the heater. Make sure it is on.
- Recent work: If the tank was recently drained, it must be completely full before power is restored. Energizing an element in an empty tank can burn it out.
Electrical causes a professional will check
- Tripped high-limit switch, which can indicate a failed thermostat or element
- Failed upper or lower element, which can cause no hot water or lukewarm water that runs out quickly
- Failed thermostats
- Loose or burned wiring connections at the heater or in the junction box
- Corrosion in coastal homes and humid garages
Do not remove access panels on an energized water heater. The terminals are live at 240 volts.
Electrician or plumber?
Breaker, circuit, and wiring problems are electrical work. Tank leaks, valves, and water connections are plumbing work. Element and thermostat replacement is often done by either trade, depending on the company.
Frequently asked questions
Why is my electric water heater not heating?
Common causes are a tripped breaker, a tripped high-limit switch, or a failed element or thermostat.
Why does my water heater breaker keep tripping?
A shorted element, a wiring fault, or a failing breaker can cause repeated trips. Leave it off and have it diagnosed.
Is it safe to reset the water heater high-limit button myself?
The reset button is behind access panels near live 240-volt terminals. Have a qualified professional test the unit, since repeated high-limit trips point to an underlying problem.
Can a water heater run on a shared circuit?
No. Electric water heaters require a dedicated circuit sized to the unit's rating.
Copperhead Electrical serves homeowners across Charleston, Mount Pleasant, West Ashley, James Island, Johns Island, Daniel Island, North Charleston, and Summerville. Call 854-444-6516 or request service online.