How Many Amps Does an Electric Water Heater Use?
Electric Water Heater draws about 17 amps at 240 volts (4,000 watts running). Electric Water Heater runs on its own dedicated 240 V circuit — plan on a 30 A double-pole breaker with 10 AWG copper.
Amps = watts ÷ volts. Enter the wattage from your appliance's nameplate or label for an exact figure.
Current draw — an electric water heater
17 A
- At 240 V
- 4,000 W
This appliance's circuit is sized from its nameplate per the NEC, not from wattage — see the circuit guidance below.
Electric Water Heater amperage at 120 V and 240 V
Same 4,000 W load — the current halves when the voltage doubles. Electric Water Heater is typically a 240 V appliance in US homes.
| Draw | Watts | Amps at 120 V | Amps at 240 V |
|---|---|---|---|
| Running | 4,000 W | 33 A | 17 A |
Breaker and circuit for an electric water heater
Electric Water Heater runs on its own dedicated 240 V circuit — plan on a 30 A double-pole breaker with 10 AWG copper. Storage water heaters are continuous duty (NEC 422.13, sized at 125%): a typical 4,500 W element needs 23+ A of capacity, and 30 A / 10 AWG is the standard circuit.
Guidance only — actual circuit sizing depends on your unit's nameplate, wire run length, and local code. Confirm with a licensed electrician. See the wire & breaker size chart for the full NEC ampacity table.
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