What Size Breaker for Dryer?
The standard electric clothes dryer requires a 30-amp double-pole breaker on a dedicated 240V circuit. This guide covers NEC 220.54 requirements, wire sizing, receptacle types, and the differences between electric and gas dryer circuits.
The Standard: 30A Breaker for Electric Dryers
Nearly all residential electric clothes dryers in North America are designed for a 30-amp, 240V dedicated circuit. This is both an NEC requirement and an industry standard that has been consistent for decades. The 30A rating covers the heating element, motor, controls, and blower fan.
A typical residential electric dryer draws between 18A and 24A during normal operation, with the heating element being the primary load. The 30A breaker provides adequate protection while accommodating startup surges from the motor.
NEC 220.54: Electric Dryer Load Calculation
NEC 220.54 provides the standard method for calculating electric dryer loads in dwelling units:
- Minimum branch circuit: 30A per NEC 220.54
- Minimum feeder demand: 5,000W (or nameplate rating if larger) per NEC Table 220.54
- Circuit rating: 30A minimum, with 10 AWG copper wire
The NEC uses 5,000W as the default dryer load for load calculations, even though most dryers are rated between 4,400W and 5,600W. This built-in margin accounts for the fact that not all dryers in a multi-unit building operate simultaneously.
Complete Dryer Circuit Specifications
| Component | Specification | NEC Reference |
|---|---|---|
| Breaker | 30A double-pole | 220.54, 210.23 |
| Voltage | 240V (120/240V split-phase) | — |
| Wire gauge (copper) | 10 AWG | 310.16 |
| Cable type | 10/3 NM-B (10/2 for 3-prong existing) | 334 |
| Receptacle (new) | NEMA 14-30R (4-prong) | 210.50 |
| Receptacle (existing) | NEMA 10-30R (3-prong, grandfathered) | — |
| Circuit type | Dedicated (dryer only) | 210.23 |
| Cord length | 6 feet maximum recommended | 422.16(B)(2) |
3-Prong vs. 4-Prong Dryer Outlets
This is one of the most common sources of confusion for dryer installations:
3-Prong (NEMA 10-30R) — Legacy
- Two hot wires (120V each) and one combined neutral/ground
- The dryer chassis is bonded to the neutral wire
- Was standard before the 1996 NEC code change
- Still legal to use on existing installations (grandfathered)
- Less safe because the chassis can become energized if the neutral breaks
4-Prong (NEMA 14-30R) — Current Standard
- Two hot wires (120V each), one neutral, one ground (separate)
- Ground and neutral are not bonded at the dryer
- Required for all new dryer installations since 1996
- Safer because the chassis has a dedicated ground path
Important: If your home has a 3-prong outlet and you're replacing the dryer, you can use a 3-prong cord on the new dryer. However, if you're running new wire or renovating, you must install a 4-prong outlet. Some dryer manufacturers include both cord types; otherwise, buy the matching cord separately.
Wire Requirements for Dryer Circuits
For a standard 30A dryer circuit:
- Wire gauge: 10 AWG copper (minimum per NEC 240.4 and Table 310.16)
- New installations: 10/3 NM-B (Romex) — black (hot), red (hot), white (neutral), bare (ground)
- Existing 3-prong: 10/2 NM-B — black (hot), white (neutral/ground), bare (ground)
- In conduit: 10 AWG THHN — four individual conductors (black, red, white, green)
For runs exceeding 100 feet, consider upsizing to 8 AWG to minimize voltage drop. Excessive voltage drop can cause the heating element to underperform and increase drying times.
Gas Dryer vs. Electric Dryer Circuits
Gas dryers have significantly different electrical requirements because the gas burner handles the heating, not an electric element:
| Feature | Electric Dryer | Gas Dryer |
|---|---|---|
| Voltage | 240V | 120V |
| Breaker | 30A double-pole | 15A or 20A single-pole |
| Wire | 10 AWG copper | 14 AWG (15A) or 12 AWG (20A) |
| Receptacle | NEMA 14-30R (4-prong) | Standard NEMA 5-15R or 5-20R |
| Circuit type | Dedicated 240V | Can share with other outlets |
| Typical draw | 18–24A | 3–5A |
A gas dryer's electrical needs are modest — just the motor, drum rotation, electronic controls, gas valve, and igniter. Most gas dryers plug into a standard 120V household outlet. Check whether your laundry area has a gas supply and appropriate 120V outlet before choosing between gas and electric models.
Common Installation Mistakes
- Using a 20A breaker: This will trip constantly. Electric dryers require 30A.
- Using a 40A or 50A breaker: Oversized breakers are a fire hazard because the wire and receptacle are rated for only 30A.
- Using 12 AWG wire: 12 AWG is rated for 20A maximum. You must use 10 AWG for a 30A circuit.
- Not using a dedicated circuit: NEC requires the dryer to have its own circuit. Sharing with a washing machine or other appliance violates code.
- Mixing 3-prong and 4-prong incorrectly: When converting from 3-prong to 4-prong, you must rewire the dryer's internal bonding jumper — remove the neutral-ground bond and connect the ground wire to the chassis ground terminal.
- Aluminum wire on a 30A circuit: If using aluminum wire, you must upsize to 8 AWG. Copper is preferred for residential dryer circuits.
Upgrading an Existing Dryer Circuit
If you're upgrading from a 3-prong to a 4-prong outlet (recommended for safety), follow these steps:
- Turn off the 30A breaker at the panel
- Verify power is off with a voltage tester
- If the existing wire is 10/3 with a ground, simply replace the receptacle with a NEMA 14-30R
- If the existing wire is 10/2 (no separate ground), you'll need to run new 10/3 cable from the panel
- Install a new 30A double-pole breaker in the panel (if not already present)
- Connect the dryer cord to match: remove the neutral-ground bonding jumper per the dryer manufacturer's instructions
Frequently Asked Questions
What size breaker does an electric dryer need?
The standard breaker for a residential electric dryer is a 30-amp double-pole breaker on a 240V dedicated circuit. This is specified by NEC 220.54 for household electric dryers.
What size breaker does a gas dryer need?
A gas dryer needs only a 120V, 20-amp circuit for the motor, controls, and igniter. A single-pole 20A breaker with 12 AWG wire is sufficient.
Can I use a 50-amp breaker for my dryer?
No. The NEC requires a 30A breaker for a standard residential electric dryer. Using a 50A breaker creates a fire hazard because the dryer wiring and receptacle are rated for only 30A. The breaker must match the circuit rating.
What wire do I need for a 30-amp dryer circuit?
Use 10 AWG copper wire for a 30A dryer circuit. For new installations (post-1996 NEC), use 10/3 NM-B (3 conductors + ground) because the NEC now requires a separate neutral and ground for dryer receptacles.
What is the difference between a 3-prong and 4-prong dryer outlet?
A 3-prong outlet (NEMA 10-30) has two hots and a neutral with no separate ground — the ground and neutral are bonded. A 4-prong outlet (NEMA 14-30) has two hots, a neutral, and a separate ground, which is safer. The NEC has required 4-prong outlets since 1996.