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Electric water heater not heating
The electrical causes of a water heater that no longer gives hot water, what you can check without opening it, and when to call.
In short
This guide covers the electric tank water heater that no longer gives hot water, and the causes that come down to electricity.
- An electric water heater has its own circuit, and the Code treats it as a continuous load (2018 edition).
- According to the manufacturer A.O. Smith, the causes to check are the power supply, the cut-off device that trips when the water gets too hot, the upper element and the thermostats.
- You can check the water heater’s breaker at the panel.
- The rest is checked under the cover, next to 240 V parts: that is an electrician’s job.
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The electrical causes
| Cause | What it means | Who checks it |
|---|---|---|
| No power | The breaker has tripped, or power isn’t reaching the water heater | You, for the breaker; an electrician for the rest |
| Cut-off device tripped | The water got too hot and the device cut the heating | An electrician |
| Upper element | It no longer heats | An electrician |
| Thermostat | At fault when the upper element is good | An electrician |
These causes come from the manufacturer A.O. Smith’s troubleshooting chart for a standard electric water heater.
The same manufacturer notes that the lower thermostat does most of the work: it is the one most likely to fail first.
If the elements and thermostats are good, A.O. Smith has you look for a leak on the hot water side of the plumbing.
What you can check
The water heater’s breaker, at the panel: for its mini-tank models, the manufacturer Bosch asks you to check that it hasn’t tripped.
If it has, you can reset it. If it trips again as soon as it’s reset, you don’t keep resetting it: you call an electrician.
If a disconnect switch is installed near the water heater, it is what cuts the appliance’s power during maintenance: see Disconnect switches: what they do.
What not to do
Don’t open the cover: it gives access to 240 V parts.
Don’t replace an element or a thermostat yourself: in Québec, electrical work is reserved for electrical contractors, even for an outlet.
When to call
Call an electrician if the breaker trips again, or if the breaker is on and the water stays cold.
Burning smell or sparks: switch off the main breaker if you can do so safely, move away and call us at 438-542-7304, 24 hours a day.
No hot water?
We replace water heater disconnects and reconnect water heaters. The exact price is written in the quote, before the work.
Send my quote requestWhat we do
Replacing the water heater disconnect is among the general electrical jobs we do most often.
A water heater to reconnect is also part of our everyday work.
The water heater has its own branch circuit (2018 edition): the details are in Dedicated circuits: which appliances need one?.
Frequently asked questions
Why has my electric water heater stopped heating?
According to the manufacturer A.O. Smith: no power, a cut-off device that tripped because the water got too hot, an upper element or a thermostat that no longer works.
Where is the reset button?
On some models, it is under the cover, next to 240 V parts: the cover stays closed. If it has tripped, the water got too hot: an electrician looks for the cause.
Does a water heater have its own circuit?
Yes. In the 2018 edition of the Code, the water heater is supplied by a dedicated branch circuit, and it counts as a continuous load.
Can I replace the element myself?
No. In Québec, electrical work is reserved for electrical contractors, even for an outlet.
No hot water and the breaker is on?
We replace water heater disconnects and reconnect water heaters; the exact price is in the quote.
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Get a quote: water heater
Sources
Consulted on October 30, 2026.