How to Hook Up a 4-Prong Dryer Cord From a 3-Prong Cord


Newer dryers have a 4-prong plug while older homes often only have 3-prong outlets. This incompatibility is due to changes to the National Electrical Code requiring a separate ground wire on dryers for safety. The 4th prong provides a path to ground that is independent from the neutral wire.

While a 3-to-4 prong adapter seems like an easy solution, it is not recommended. Adapters defeat the extra safety provided by the 4-prong connection. However, with the right 4-to-3 prong adapter and wiring configuration, you can safely connect your dryer without compromising grounding.

Gather the Necessary Materials

Before getting started, make sure you have these materials available:

  • 4-prong dryer cord
  • 4-to-3 prong adapter
  • 3-wire electrical cord
  • Wire nuts
  • Electrical tape
  • Phillips screwdriver
  • Needle nose pliers

Optional but recommended materials:

  • Circuit tester
  • Multimeter

Safety gear:

  • Work gloves
  • Safety glasses
  • Dust mask

Turn Off Power to Outlet

Before doing any work, make sure to shut off the circuit breaker for the outlet you’ll be working on. This is an important safety step when dealing with household electrical.

Identify Wiring in 3-Prong Outlet

Remove the outlet cover plate and unscrew the outlet from the electrical box. You’ll see 3 wires attached to the outlet – a black hot wire, a white neutral wire and a ground wire which could be bare copper or green.

Make note of the exact wiring configuration. You’ll need to replicate these connections in the 4-to-3 prong adapter.

Connect the Adapter

Following the wiring diagram that came with your specific adapter, connect the black hot wire to the brass screw, the white neutral wire to silver and the ground wire to green.

The most common way to configure the ground wire is to attach it to the green ground screw on the adapter. However, check your adapter’s instructions to be sure.

Use wire nuts to secure the connections and electrical tape to cover them. This prevents wires from loosening and touching.

Connect Dryer Cord

With the outlet wiring completed, plug in the 4-prong dryer cord to the adapter. Make sure it is pushed securely into place.

Connect the neutral wire (white or center wire) from the dryer to the neutral terminal (silver screw) on the adapter.

Attach the two hot wires from the dryer (red and black) to the brass screw.

Finally, connect the ground wire from the dryer (green or bare) to the ground terminal (green screw) on the adapter.

Reinstall Outlet

Carefully position the outlet and adapter back into the electrical box. Screw it securely in place along with the cover plate.

Restore power to the circuit at the breaker box. You’re now ready to safely operate your 4-prong dryer.

Test Setup

Before using your dryer, test your work. Plug a circuit tester into the outlet and make sure the lights indicate proper wiring.

You can also use a multimeter to check continuity between neutral, hot and ground. If testing reveals any issues, double check connections before using.

Safety Tips

When converting a 3-prong to 4-prong outlet, keep these safety guidelines in mind:

  • Shut off power at the breaker before starting
  • Use caution and wear protective gear when working
  • Follow wiring diagram for your specific adapter
  • Make secure connections (no exposed wire)
  • Don’t use 3-to-4 prong plug adapters
  • Label wires to avoid confusion
  • Test setup before running dryer

Converting to a 4-prong connection is well worth it for the added safety. Take care when working with household electrical and consult an electrician if needed. With the proper materials and safe setup, you can DIY the conversion from 3 to 4 prongs.

Frequently Asked Questions

What is the difference between 3-prong and 4-prong outlets?

3-prong outlets have a hot, neutral, and ground wire. 4-prong also has a dedicated neutral wire, providing an independent path to ground that does not rely on neutral.

Why can’t I just use a 3-to-4 prong adapter?

Adapters allow a 4-prong plug to fit into a 3-prong outlet but do not provide the proper separate grounding of a 4-wire connection. This defeats the safety enhancement.

How do I identify the outlet wires?

Black is hot, white is neutral, and the bare copper or green wire is ground. Make sure to mark and label wires when disconnecting the outlet.

Can I use this adapter on all 3-prong outlets?

No, it depends on how your home is wired. Some older homes have outlets wired without a proper ground wire, making a 4-prong connection unsafe.

What should I do if there is no ground wire at the 3-prong outlet?

It’s best to hire an electrician to assess your wiring and install a new grounded outlet if needed. Do not attempt to install a 4-prong adapter without an adequate ground connection.

Can I connect two hot wires to one brass screw on the adapter?

It’s best to join the two hot wires with a wire nut and connect that to the brass screw to avoid overheating. Do not connect wires to any screw on an adapter not designed for multiple wires.

What should I do if the outlet has aluminum wiring?

Connecting copper and aluminum wire requires special techniques. Hire a qualified electrician if your existing outlet has aluminum wiring. Do not attempt to mix wire types yourself.

Why do I need to label and mark the outlet wires?

Correctly labeling each wire as hot, neutral or ground ensures you reconnect them properly to the adapter. Mixing them up poses a serious shock and fire hazard.


While the wiring may seem complex at first, converting an old 3-prong outlet to work with a 4-prong dryer is completely doable with some basic skills. The most important steps are using the right adapter for your home’s wiring, making secure connections, testing your work, and following proper safety precautions.

Take your time, be extremely careful working with electrical connections, and consult an expert if any issues come up. With the right materials and proper technique, you can safely connect that 4-prong dryer in no time. Enjoy the peace of mind and added safety with your new modern dryer setup.