Electric Dryer Wire Size — 240V NEC Circuit Guide

The standard residential dryer circuit uses #10 AWG copper, a 30A double-pole breaker, and a NEMA 14-30 outlet (4-wire). NEC 250.140 requires 4-wire connections for all new dryer installations. This guide covers wire sizing, breaker selection, outlet types, and the critical 3-wire vs. 4-wire distinction.

Electric Dryer Circuit — Quick Reference

Wire Size (copper)#10 AWG — 35A rated at 75°C
Wire Size (aluminum)#8 AWG — 40A rated at 75°C
Breaker Size30A double-pole
Outlet Type (new install)NEMA 14-30 (4-wire, 240V)
Voltage240V single-phase
NEC SourceTable 310.15(B)(16), NEC 250.140
Verify Wire Size & Voltage Drop →

Standard Dryer Wiring Overview

Standard residential electric dryers are rated 500–5500 watts at 240V, drawing up to 22–25A when the heating element and motor run together. A 30A circuit with #10 AWG copper provides the required protection and capacity for all UL-listed residential dryers.

The circuit must include a 30A double-pole breaker to protect both hot conductors simultaneously. The outlet must be within reach of the appliance cord (typically 6 feet). NEC 422.10 provides additional requirements for appliance branch circuits.

3-Wire vs. 4-Wire Dryer Wiring — Critical Difference

This is the most common source of confusion and error in dryer installations:

  • 3-wire (NEMA 10-30): Hot, Hot, Neutral — the neutral wire served as the equipment chassis bond. This was permitted before the 1996 NEC update. It is now prohibited for new installations because a broken neutral can energize the dryer chassis.
  • 4-wire (NEMA 14-30): Hot, Hot, Neutral, Ground — separate neutral and equipment grounding conductors. Required for all new dryer circuit installations under NEC 250.140.

If you are replacing a dryer in an older home with a 3-wire outlet, you are permitted to keep the existing 3-wire connection as a grandfathered installation. However, if you are replacing the receptacle, running new cable, or building new, you must use 4-wire and a NEMA 14-30 outlet.

Many new dryers ship configured for both 3-wire and 4-wire connection via a terminal block — follow the manufacturer instructions when changing configurations.

Related Tools & Guides

30-amp wire size guide — NEC reference for copper & aluminum Wire size calculator — verify for your dryer circuit length Circuit breaker size calculator Electric range wire size guide — 50A circuits

Frequently Asked Questions

#10 AWG copper (or #8 AWG aluminum) with a 30A double-pole breaker. Per NEC Table 310.15(B)(16), #10 AWG copper is rated 35A at 75°C, satisfying the 30A breaker requirement.

3-wire (NEMA 10-30) has hot, hot, and neutral — with the neutral bonded to the chassis. 4-wire (NEMA 14-30) has hot, hot, neutral, and a separate ground. NEC 250.140 requires 4-wire for all new dryer circuit installations since 1996. Existing 3-wire circuits can be grandfathered.

A 30A double-pole breaker for standard residential electric dryers. Some high-capacity or combination washer-dryer units may require 40A — always check the appliance nameplate.

No. #12 AWG is rated 20A at 75°C, which is insufficient for a 30A circuit. NEC 240.4 requires the conductor to be protected at or below its rated ampacity. Use #10 AWG copper minimum.

New installs: NEMA 14-30 (4-wire, 240V). Existing grandfathered installs: NEMA 10-30 (3-wire) may remain, but cannot be installed new per NEC 250.140.

Standard dryer circuits are 10–30 feet and voltage drop is rarely an issue. At 30 feet, #10 AWG copper on 240V/30A is about 1.2% drop. If your dryer is unusually far from the panel, verify with the calculator.