NEC Wire Sizing
What Size Wire for a Dishwasher?
The breaker, copper and aluminum wire, and ground for a typical dishwasher circuit, with the NEC basis and the nameplate caveats that actually decide it.
Dishwasher Circuit Spec
| Voltage | 120V |
| Breaker | 20A GFCI |
| Copper wire | #12 |
| Aluminum wire (75°C, SER or conduit) | #10 |
| Equipment ground (Cu) | #12 |
A built-in dishwasher uses a dedicated 120V 20A circuit. It must be GFCI protected (210.8) and, under the 2023 NEC, AFCI protected. Some compact units fit a 15A circuit; a hardwired unit still needs its own circuit. Wire sized at NEC Table 310.16 (copper lead at the 60°C column for NM-B); ground per NEC Table 250.122. The appliance nameplate lists the exact minimum circuit and maximum breaker; it always governs over a typical value.
Aluminum branch conductors are 75°C-rated AA-8000 alloy (SER cable, or XHHW-2 / THWN-2 in conduit); there is no 60°C aluminum NM-B, so the aluminum row uses the 75°C column. Where the terminations are rated 60°C only, size aluminum from the 60°C column instead (#10 here).
Adding this as a new load? Check whether your panel can handle it (the NEC 220.87 service check), or compare it against the breaker size by load chart.
Long Run? Size It Exactly
For a long run where voltage drop matters, or a nameplate that differs from the typical value, enter your exact load, distance, and conditions.
Frequently Asked Questions
What size wire do I need for a dishwasher?
A dishwasher typically uses a 20A / 120V circuit, which calls for #12 copper (or #10 aluminum) conductors and a #12 copper equipment ground per NEC Table 250.122. A built-in dishwasher uses a dedicated 120V 20A circuit. It must be GFCI protected (210.8) and, under the 2023 NEC, AFCI protected. Some compact units fit a 15A circuit; a hardwired unit still needs its own circuit.
What size breaker for a dishwasher?
A 20A single-pole (120V) breaker. The #12 copper conductors are matched to that 20A rating, and it must be a GFCI breaker (or GFCI protection ahead of the appliance). Do not oversize the breaker to a wire it does not protect: the breaker and the conductor go up together. Always confirm against the appliance nameplate, which lists the exact minimum circuit and maximum overcurrent device.
Does a dishwasher need GFCI protection?
Yes. Current NEC requires GFCI protection for this appliance (NEC 210.8). Use a GFCI breaker or a GFCI device ahead of it.
Can I use aluminum wire for a dishwasher?
Yes. On the 75C column (the usual basis for aluminum), a 20A circuit needs #10 aluminum, versus #12 copper. Aluminum is common on larger circuits and services to save cost; apply antioxidant to the terminations, torque to the listed spec, and remember aluminum drops slightly more voltage on long runs.
Wire Size for Other Appliances
Electric Dryer
#10 copper on a 30A / 240V circuit.
Electric Range
#6 copper on a 50A / 240V circuit.
Electric Wall Oven
#8 copper on a 40A / 240V circuit.
Electric Cooktop
#8 copper on a 40A / 240V circuit.
Electric Water Heater
#10 copper on a 30A / 240V circuit.
Hot Tub
#6 copper on a 50A / 240V circuit.
Garbage Disposal
#14 copper on a 15A / 120V circuit.
Built-In Microwave
#12 copper on a 20A / 120V circuit.
Refrigerator
#12 copper on a 20A / 120V circuit.
Freezer
#12 copper on a 20A / 120V circuit.
Garage Door Opener
#12 copper on a 20A / 120V circuit.
Wire Size Calculator
Full NEC 310.16 sizing for any load, distance, and conditions.