How to Convert a 3-Prong Dryer Cord to a 4-Prong: Upgrade for Better Safety

If you move into a newer home, you may discover that the laundry room has a 4-prong outlet, while your older dryer has a 3-prong cord. To meet modern electrical codes and improve safety, you’ll need to upgrade your dryer to a 4-prong cord.

This guide explains how to safely change a 3-prong dryer cord to a 4-prong cord, with a wiring diagram and step-by-step instructions.

Why Upgrade to 4-Prong?

• 3-Prong System (Old Standard): Neutral and ground are combined. Risk of the dryer chassis becoming energized.

• 4-Prong System (Current Standard): Neutral and ground are separated, providing a safer path in case of a fault.

• NEC Requirement: Since 1996, new homes must use 4-prong outlets.

What You Need

• Tools: Screwdriver, pliers, wire stripper.

• Materials: A new 4-prong dryer cord.

• Safety: Unplug the dryer or turn off the breaker.

Step-by-Step: Converting 3-Prong to 4-Prong

1. Remove the cover
   Open the dryer’s rear access panel.

2. Disconnect the old 3-prong cord

   • Three wires: red (L1), black (L2), white (neutral/ground).

   • Note: In a 3-wire system, the white neutral wire was bonded to the chassis.

3. Install the new 4-prong cord

   • Red → L1 terminal

   • Black → L2 terminal

   • White → Neutral terminal (center)

   • Green → Ground terminal (connected to dryer chassis)

4. Remove the bonding strap

   • If there is a ground strap connecting neutral to the chassis, disconnect it.

   • Neutral and ground must be separate in a 4-wire system.

5. Secure and close

   • Tighten the strain relief clamp.

   • Reinstall the access panel.

Wiring Diagrams

3-Prong Dryer Cord Wiring

• L1 = Red

• L2 = Black

• Neutral/Ground = White (bonded to chassis)

4-Prong Dryer Cord Wiring

• L1 = Red

• L2 = Black

• Neutral = White

• Ground = Green (separate)

Using a 3-Prong to 4-Prong Adapter

Yes, 3-prong to 4-prong adapters exist, but they are not recommended for long-term use because they still lack a true separate ground. The safest option is always replacing the cord.

Conclusion

Upgrading to a 4-prong dryer cord improves safety and ensures compliance with modern electrical codes. While adapters may offer a quick fix, the best solution is a proper cord replacement.

👉 For the opposite conversion, see our guide: “How to Change a 4-Prong Dryer Cord to a 3-Prong: Step-by-Step Guide with Wiring Diagram”.