Dishwasher Amps, Watts & Breaker Size
A built-in dishwasher is about 10 A and 1,200 to 1,500 W on a dedicated 15 A circuit; a heated-dry model climbs to about 12 A and 1,800 W and belongs on 20 A. What the spec does not tell you is whether the connection already in your sink cabinet is dedicated, GFCI-protected, or quietly shared with the disposal — the…
Dishwasher Power Requirements at a Glance#
A built-in dishwasher runs on a 120 V supply and wants a circuit of its own, either hardwired at a junction box or plugged into a single 5-15R receptacle under the sink. A standard unit draws about 10 A and 1,200 to 1,500 W on a 15 A breaker; a heated-dry model reaches about 12 A and 1,800 W and is specified for 20 A. That is the whole specification — and it assumes a dedicated circuit most kitchens were not built with. The table below reads the cabinet you actually have back as a verdict.
Dishwasher Electrical Specifications#
| Configuration | Voltage | Amps | Watts (max load) | Breaker | Outlet (NEMA) |
|---|---|---|---|---|---|
| Built-in dishwasher (hardwired or plug-in) | 120 V | 10 A | 1,200–1,500 W | 15 A | 5-15R |
| Dishwasher with heated dry on a 20 A circuit | 120 V | 12 A | 1,800 W | 20 A | 5-15R |
A dishwasher spends most of a cycle pumping quietly and then spikes when the heating element dries the load, so it earns a circuit of its own rather than sharing with the disposal on the other side of the cabinet. Some models cord-connect to a receptacle in the sink base while others splice into a junction box.
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What is in your sink cabinet now, and what it will take#
Open the cabinet beside the dishwasher and look at how the supply arrives, then trace it to the breaker that feeds it.
| What you find | What it is | Verdict |
|---|---|---|
| A single 5-15R receptacle on its own 15 A breaker | A dedicated cord-connected appliance circuit | Runs a standard built-in at about 10 A; a heated-dry model at 12 A and 1,800 W is specified for the 20 A feed instead |
| A junction box and a whip, no receptacle | A hardwired dedicated circuit | The same machines — the supply lands in the dishwasher junction box rather than a plug, and the appliance shutoff still has to be reachable |
| One receptacle feeding both the dishwasher and the disposal | A shared circuit, which is not what manufacturers specify | Expect nuisance trips whenever the drying heater and the disposal run together; the machine is specified for a branch of its own |
| No GFCI protection upstream of the under-sink receptacle | An older kitchen circuit | It will run, but current rules generally require the receptacle serving the dishwasher to be GFCI-protected |
| A heated-dry model on the label and a 15 A breaker in the panel | A 20 A machine on a 15 A branch | The trip is the circuit doing its job at about 12 A and 1,800 W. The fix is the correct 20 A circuit with its heavier conductor, pulled by a licensed electrician — never a larger breaker on the same wire |
Two configurations are counted above, separated by the heated-dry element. Both assume something most kitchens were not built with — a branch serving the dishwasher alone — so the specification and the cabinet under your sink routinely disagree, and it is the cabinet that has to change.
Circuit and Breaker Sizing for the Dishwasher#
A dishwasher is sized as a dedicated appliance circuit because its motor and heater run together during a cycle. At about 10 A the standard machine is protected by a 15 A breaker, and the conductors match that breaker's rating; a unit with a heated-dry heater pushes closer to 12 A and 1,800 W, which is why manufacturers spec it onto a 20 A circuit with a correspondingly heavier conductor. A dedicated branch circuit is required rather than optional: sharing the feed with the disposal or the kitchen counter receptacles risks tripping the 15 A breaker every time the heater and another load run at once. Whether the unit is hardwired or fitted with a 5-15R plug, that circuit serves the dishwasher alone.
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Installation and Safety Notes for Dishwasher Wiring#
Matching the connection to the circuit means either landing the supply in the dishwasher’s junction box or fitting a single 5-15R receptacle in the adjacent sink cabinet for a plug-in cord kit. Under current rules the under-sink receptacle serving the dishwasher generally needs GFCI protection, and a new dedicated circuit is permitted-and-inspected work. A confident homeowner can often connect the appliance whip to existing supply, but adding a new dedicated 120 V circuit back to the panel — landing a 15 or 20 A breaker and pulling the conductor — is a job for a licensed electrician, who will also confirm the GFCI and the required appliance shutoff.
Dishwasher Electrical FAQ#
Does a built-in dishwasher need a dedicated circuit?#
Yes. Manufacturers spec a dedicated 120 V circuit so the motor and heater have the full 15 A (or 20 A with heated dry) to themselves. Sharing the feed invites nuisance trips when another load runs at the same time.
What breaker size does the machine usually take?#
A standard dishwasher drawing about 10 A sits on a 15 A breaker. A model with a heated-dry element draws closer to 12 A and 1,800 W and belongs on a 20 A circuit.
Can it share a feed with the sink-side disposal?#
It should not. Both are dedicated-circuit appliances; pairing them on one 15 A circuit means the disposal’s motor surge and the dishwasher’s heater can trip the breaker together. Give each its own line.
Is the unit hardwired or plugged into an outlet?#
Either is allowed. Many dishwashers are hardwired at a junction box, but a plug-in cord kit landing in a single 5-15R receptacle in the sink cabinet is equally common and makes future service easier.
Why might it trip the breaker during the heated dry?#
The heated-dry element is the biggest single draw in the cycle, pushing the unit toward 12 A and 1,800 W. On a shared or undersized 15 A circuit that surge can trip the breaker; a dedicated 20 A circuit solves it.
Does the under-sink receptacle require GFCI protection?#
Under current code the receptacle serving a dishwasher generally must be GFCI-protected. An inspector will check for it on new work, so plan the outlet or breaker accordingly.
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