The National Electric Code changed the wiring for the electric cloth dryer outlets in 1996. Before the change, the dryer used to have 3-slot devices. After the change, they had 4 slots that accept only 4-prong electric cords. So, where does the ground wire go in both the prong dryers?
If you have a 3-prong dryer, the ground will stay as it is in the outer block terminal at the top and won’t go anywhere. The ground wire in the 4-prong dryer cords will go to the ground terminal with the ground screw. It prevents the appliance’s metal case from getting energized.
This article will help you know where the ground wire goes in the 3 and 4-prong dryers. We shall also share the difference between these two prongs and how to hook a 4-prong dryer from a 3-prong.
What is the difference between a 3-prong and a 4-prong dryer?
Before the 2000s, it was common for dryers to take power from only the 3-prong cords and outlets.
The 4-prongs have now become common in recent times.
Understanding the difference between the two prongs will let you know how to use them and why nowadays people change from a 3-prong to a 4-prong.
When you shift to a new house, you might have a dryer that does not match the house’s existing outlet.
So, you need to familiarize yourself with the various types of outlets and make sure that the dryer cord is compatible.
If not, then how to make it compatible?
In the old times, it was common for houses to have dryers with a 3-prong cord.
A 3-prong dryer cord configuration has three wire connections, two hot and one neutral.
But a 3-prong outlet has one hot, one neutral, and one grounding.
When you connect the cord to the outlet, two prongs in an outlet will serve for two positive wires, and the third one will serve for the neutral wire.
Since the neutral wire is connected to the grounding, it works as the ground wire.
A grounding is responsible for protecting us from electric shocks during short circuits.
Since the neutral works as the grounding, there is no need for a separate ground connection.
A 3-prong dryer outlet can give electric shocks due to the moisture from the laundry.
That is why even if the neutral works as the grounding, a 3-prong is not very safe.
In most areas, a 3-prong dryer outlet is not allowed to be used or installed because it does not meet the code requirements of electricity.
If you live in a house with a 3-prong dryer outlet and your dryer is also a 3-prong, you do not need to upgrade.
The 4-prong dryer cords will have four wire connections – two hot, one neutral, and one ground.
The 4-prong outlet too will have the same setup.
So, you need a 4-prong outlet to match the dryer cord.
Here, you do not have to connect the neutral wire to the ground but to the neutral terminal, which minimizes the risk of electric shocks.
That is why this prong is widely used nowadays.
These prongs were generally determined to be used for 240V dryers so that the neutral and the ground paths could remain in separate wires.
Mixing both can create severe electric shocks, especially if the outlets are situated in the laundry rooms.
Where does the ground wire go on a 3-prong dryer?
A 3-prong dryer will have three wire connections.
When you use a 3-prong dryer cord, you must connect two hot wires to two prongs and one to the neutral.
Make sure that the cord matches the outlet pattern.
Once you pick up the right cord, remove the access panel from the appliance’s back and expose the terminal block and wire connections.
There will be a 4-wire cable with white, green, red, and black wires.
The red and black are the hot wires, white is the neutral wire, and green is the ground wire.
The green wire is to ground the metal case inside the dryer’s back panel.
In a 3-prong cord, there won’t be any ground wire, only two hots and one neutral.
So, the existing green wire in the case will remain on an outer block terminal screw somewhere at the top.
This green wire is a ground wire which should not go anywhere.
Let it stay in its place.
Sometimes, there might be a grounding strap instead of the wire.
It should go between the central terminal and the dryer case.
The two hot wires will go to the left and right terminal screws, and the white wire to the central terminal with a ground screw.
Some people connect the ground wire to the central terminal screw.
It can be dangerous as the ground wire won’t be able to save you from electric shock anymore.
However, if your circuit is 220-240V, you may risk connecting the ground wire to the central terminal to ground your outlet.
Otherwise, if the circuit is 120V, let the ground wire stay where it is.
Since you connect the neutral wire to the central terminal, it will work as the grounding.
Where does the ground wire go in a 4-prong dryer?
A 4-prong dryer has a separate screw terminal for the ground wire.
That is why this type is widely used nowadays.
People who own 3-prong dryers convert to 4-prong dryers.
A ground wire creates an alternate path for the electricity to flow when there is a short circuit.
So, the current passes through the grounding instead of flowing through your body.
That is why it is considered the safest one nowadays.
First, you must open the access panel and expose all the screws, terminals, and wire connections.
So, the ground wire you have will go to the grounding terminal of the dryer.
To connect the wires, loosen all the screws securing the ends of the existing dryer cord wires to the terminal block.
The central screw will be silver, and the other two screws will be yellowish brass.
There will be a screw centered below the top middle screw.
This screw holds a small metal ground strap.
The white wire at the 4-prong dryer will go to the center terminal block using the silver screw.
The black wire will go to the left terminal block and red to the right terminal block with the yellow screw.
The ground wire will go to the place of the grounding strap, replace the strap, and be secured with the ground screw.
A 4-prong dryer is the safest as it has separate ground and neutral connections.
You do not have to leave the grounding behind or connect it to the neutral connection as you do with the 3-prong dryers, no matter which circuit volt you have.
Since the ground and neutral are separate in the 4-prong dryers, there are fewer chances of electric shock.
How to hook a 4-prong dryer cord from a 3-prong dryer?
There is a difference in the wiring of these two dryers.
In a 3-prong, the neutral wire is connected to the grounding screw and the other hot wires in their respective terminals.
In a 4-prong wire, the ground and neutral have separate wires and terminals, which reduces the chances of electrical shocks.
That is why people convert from a 3-prong to a 4-prong.
Since you won’t be working with household circuit wires while changing the cord, it is safe.
Ensure that the wire connections you make while installing and combining the cord to the appliance are done perfectly and with good security.
Loose connections can cause short circuits and sparks once you plug in the appliance and start it for usage.
Once you have connected all the wires, pull them slightly to make sure they are secured enough.
Moving the appliance can increase the pressure.
So, always attach the strain relief fitting to reduce the pressure on the wirings.
Do not ever plug in the dryer cord unless you connect it properly to the dryer.
Plugging in the cord will send a 240-volt current to the bare wire ends of the dryer cord.
If the wire ends ever touch together, there will be serious short circuits and sparks.
- Phillips Screwdriver
- Nut driver or socket wrench
- Adjustable pliers.
- 4-prong dryer cord
- Strain-relief fitting for the cord
Remove the cover plate
Unplug the dryer from the electrical source to avoid electric shocks.
Turning off the circuit connected to the dryer would be even better.
Remove the metal plate that covered the cord wiring connections of the dryer’s back.
It will be above the place where the cord comes out.
You can use a magnetic screwdriver, nut driver, or socket wrench to remove the plates’ screws.
Magnetic screwdrivers do not drop the screws inside the dryer.
Remove the strain-relief fitting.
Unscrew the screws on the strain-relief fitting securing the cord to the dryer’s back panel.
Separate the fittings into two halves and pull them out of the holes one by one.
Disconnect the old cord.
Remove the screws securing the wire ends to the dryer’s terminal and disconnect the old cord.
The two outer terminals are the hot wires, and the central one will be the neutral wire.
Pull the cord through the hole and remove it.
Separate the dryer’s neutral from the ground.
Remove the neutral wire from the ground screw and cover the wire configuration from a 3-prong to a 4-prong.
Now you can have any one configuration:
- You may have a white wire inside the dryer, which is connected to the ground screw. You need to remove it and connect it to the neutral terminal on the dryer’s block OR,
- You will have a short white wire or a metal strap connected to the neutral terminal on the wire block and ground screw. Remove this wire or strap from the ground screw.
Connect the new 4-prong cord.
Install the new cord by inserting the loose wire ends through the same hole in the dryer’s back panel.
Connect the wires in the following manner:
- Connect the green wire to the ground screw.
- Connect the white wire to the central terminal for a neutral connection.
- Connect the black wire to either the left or right terminal.
- Connect the red wire to the other leftover terminal.
- You may interchange the hot wires’ position, but only connect one wire to one terminal.
Tighten the wires with screws properly and double-check everything.
Attach the strain relief fitting to the new cord.
For a new strain relief fitting, slip the tab from the fitting’s top half and place the fitting’s saddle over the top.
Repeat the same process with the bottom half of the fitting under the cord.
Squeeze both halves together and secure them with the fitting screws.
You can also use pliers to squeeze them gently if you cannot do it with your hands.
Snug the cords to hold the cords firmly.
Make sure to use only a little pressure, which can cause deformation.
If the strain relief fitting is old, it might not work well with the 4-prong cord.
A 3-prong cord is flat, and a 4-prong is round.
So, it would be best to have a fitting with a rounded center.
Do not use any fitting that does not match the cord.
Reinstall the dryer’s cover plate.
Install the cover plate back with the screws.
To test the dryer, check the control knob and see that everything is in the ‘off’ position.
Plug the dryer into the 4-prong dryer outlet.
Now, run the dryer for a few minutes and check if everything is working fine or not.
Dryers come in both 3 and 4-prong.
A 3-prong does not use the ground wire and remains in the dryer’s outer block terminal.
The grounding strap stays between the dryer case and the central terminal but does not stay connected to the terminal.
The neutral wire goes to the central terminal with the ground screw.
Sometimes, the ground wire of the appliance goes to the central terminal of the 3-prong dryer.
But, this risk is only taken if the circuit is 240V and not 120V.
In a 4-prong wire, a white wire is connected to the ground screw.
Remove it and connect it to the central terminal with the silver screw.
Take the ground wire to the ground terminal and connect it with the green screw.
This setup is safe because the neutral and ground have their terminals and screws.
So, many people consider hooking the dryer from a 3-prong to a 4-prong.
If you wish to do the same, you can follow my shared steps or hire a professional.
Can I use prong adapters?
Do not use prong adapters if your cord and outlet do not match.
The adapter won’t be able to give enough grounding path to the current during electric shocks, therefore giving you dangerous electric shocks, fire hazards, etc.
Do I need to ground the dryer?
It is mandatory to ground a dryer.
The National Electric Code, or NEC, recommends a ground wire for the dryers.
Ground wires will create an alternate path for the current flow during short circuits and avoid electric shocks and fire hazards.
Reference: Appliance wiring Wikipedia.