If you have a 220 Volt outlet that you need wired up and only have 3 wires, but you are not 100% sure how to do it, you have come to the right place!
In this guide, you will learn:
- How to safely wire up a 220 V outlet using only 3 wires
- How to tell the difference between the 2 different types of 3 wire plugs
- Why it is important not to pinch wire insulation under your termination screw
- And more!
Many people don't know there are two types of 3-prong 220 outlets that requires different wiring. How you plan on using the outlet will determine how it needs to be wired.
As a licensed electrician, I ask that if you are uncomfortable or run into problems at any time while working on wiring the outlet please stop and call a local electrician to come and finish the job.
Keep reading to learn the 7 -steps on how to wire up a 3-wire 220V outlet!
What You Need To Know About Wiring A 220V 3-Prong Outlet With Three Wires
Wiring a 3-prong 220 outlet can be a pretty easy task for a homeowner as long as they respect electricity and understand what they are working on.
It is very important that before beginning that you verify that there is no power on the wire. Electrical shocks can be very dangerous, and safety needs to be a priority! Most jurisdictions also require electrical permits for new outlets which will require a small fee.
To make sure you are installing the outlet safely, you need to know the amp draw of the piece of equipment. This will ensure you have the proper plug and the proper wire size to carry the load of the equipment.
Two Styles of 3-Prong 220 Outlets
Another important thing that you need to pay attention to is the difference between the two styles of 3-wire 220 plugs. One style will require a neutral or a white wire plus the two hot wires which typically are red and black. The other requires a ground wire which can be bare copper or green insulated along with the two hot wires. Interchanging the two can cause damage to the equipment.
It is critical to understand that a plug that requires a neutral is not able to be replaced with a plug that only requires a ground as the third wire. Any appliance that utilizes 110V power for features like a clock or timer must have a neutral or white wire. If the equipment only needs the 220 V power then no neutral is required and the 3rd wire will be the ground.
Use Crimping Or Screw
When getting ready to wire the outlet, there is two ways to wire it. One is to wrap the wire around the screw, then tighten it down. The other is to crimp a ring lug to the end of the wire which allows you to remove the screw from the receptacle, put it through the hole in the lug, and then tighten it down. Using a ring lug allows you to ensure a good tight connection!
Supplies You'll Need To Wire a 220-Volt Plug With 3-Wires
- Voltage Meter - A voltage meter allows you to verify the power is off
- Screwdriver - A screwdriver will be used to make the wire terminations and install the cover of the outlet
- Wire Strippers - Wire strippers will be used to strip the insulation off the individual wires
- Utility Knife - A utility knife will be used to remove the outer jacket to expose the individual wires
- Electrical Tape - Electrical tape will be used to wrap the outlet around the termination screws as another layer of safety
- Wire Crimpers (Optional) - Wire crimpers are used to crimp ring lugs on the ends of the individual wires
- Ring Lugs (Optional) - Ring Lugs can be crimped on the end of the individual wires allowing for a more secure connection
How To Wire a 220V Plug With 3-Wires (7-Step Guide)
- Identify Your Amperage and Wire Gauge
- Verify There is No Power
- Strip the Outer Cable Jacket
- Strip the Ends of the Individual Wires
- Crimp the Ring Lugs On or Skip to the Next Step if Not Using Them
- Terminate the Wires
- Double Check Connections and Finish
Step 1 - Identify Your Amperage and Wire Gauge
Identify the amperage and wire gauge required for your circuit.
The amperage will determine what wire gauge or thickness of wire you will need. It is important that this is sized properly so that it can handle the amount of current or amperage running through the wire. It also ensures that your circuit breaker will be able to do its job protecting you and your equipment.
- 10-Gauge wire is suitable for 30-amp receptacle
- 8-Gauge wire is suitable for 40-amp receptacle
You can use wire that is rated higher than the amperage rating of your plug but you CANNOT use wire that is rated lower!
Step 2 - Verify There is No Power
Verify there is no power on the wire you are hooking up by using your voltage tester.
Carefully use one probe to touch the end of a hot wire while touching the other probe to a ground wire; your meter should read zero volts.
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Step 3 - Strip the Outer Cable Jacket
Strip the outer cable jacket by using the utility knife to gently slice through the outer insulation.
Be careful while doing this to ensure you don't cut too deep and damage the insulation on the individual wires. You will want to strip the jacket back far enough you can easily land the wires on their respectable screws without going too far so that the wires will be exposed on the exterior of the box.
Step 4 - Strip the Ends of the Individual Wires
Strip the ends of the individual wires so you can wire them.
How much you strip off depends on if you are using ring lugs or if you are wrapping the wire around the screw.
If you are using ring lugs, strip off just enough wire so that you can slide the barrel of the ring lug over the stripped wire. You don't want much bare wire hanging out of the barrel, nor do you want insulation crimped underneath the barrel.
If you are wrapping the wire around the screw, you will strip off approximately 1 inch of insulation. Then take the tip of your strippers and pinch the end of the wire and curl it around so the end of the wire can hook over the screw.
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Step 5 - Crimp the Ring Lugs On or Skip to the Next Step if Not Using Them
Crimp the ring lugs on each of the three wires individually.
Push the wire through the barrel of the ring lug until the end of the wire is just past the end of the barrel. You don't want to push it too far or it will interfere with tightening the screw down.
Then place your wire crimpers around the barrel and squeeze. After you crimp it, tug on the ring lug trying to pull it back off the wire. You want to make sure it is securely crimped on to the wire. If it is loose, it can create a hot spot which can lead to a fire, or it will not allow power to pass through.
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Step 6 - Terminate the Wires
Terminate the wires and finalize the connections.
If you are using the ring lugs, locate one of the black or brass screws on the back of the receptacle and using the screwdriver remove it completely. Slide the lug of one of the hot wires, either the red or the black, over the screw and screw it back into the receptacle. Remove the other black or brass screw and slide the lug of the other hot wire on and screw it back in.
Locate the 3rd screw. Depending on the application you are using it for, the screw will be either green or silver. If it is green, you should be hooking up a green or bare wire. If it is silver then you should be hooking up a white wire. Take the last wire and again remove the screw slide the lug over and replace the screw back into the receptacle.
If you are just looping the wire over the screw, follow the same process as the ring lugs, just in this case you don't have to remove the screw. You can just loosen it enough to slide the hook of the wire over top and tighten it down until the wire is secure. Verify you do not have insulation pinched underneath the screw! This too can create a loose connection causing problems of no power, hot spots, and/or fire.
Step 7- Double Check Connections and Finish
Double check that you have secure connections, no loose ring lugs, or that the screw is tightened down on the wire tightly.
If everything looks good take and wrap electrical tape around the plug covering the screws and any bare wire. This provides protection from someone receiving a shock or the wires touching and shorting out.
Once you are satisfied, you can carefully tuck the wires into the box, mount the outlet, and put the cover on. Once the cover is securely in place, you can turn your power back on.
Frequently Asked Questions
What Is The Point of a 220V Outlet?
The point of a 220V plug or outlet is to provide higher power to certain home appliances such as certain dryers, ovens, air conditioners, freezers, and more.
Some high-powered tools such as air compressors or welders also require higher voltage outlets in order to work properly.
How Do You Wire a 220V 3 Prong Plug?
You should have two wires that are black and red, these are your hot wires. They will land on the black or brass screws of the plug.
The third wire will be either green or white. This wire will land on the last screw that will be silver or green.
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How Many Wires Do You Need for 220V?
You need 3 to 4 wires for 220V.
Not all applications that require 220V power require a neutral or a white wire. What it does require is two hot wires, typically red and black, and a ground wire that is green or bare.
Does 3 Wire 220 Have A Ground?
In a 220-volt circuit, any stray voltage can be carried by a neutral/ground wire.
This way of wiring does allow the stray voltage to make it to the equipment or appliance that is being powered up, allowing potential for the user to get an electrical shock.
The safest way to wire something that requires a neutral is with a 4-wire outlet. This allows for the ground and neutral to be separate and any stray power to run safely to ground.
Where Do You Bond Ground and Neutral For 3-Prong 220 Outlets?
The ground and neutral are bonded in electrical panels. Neutral wires coming into an electrical panel are landed on a neutral bus bar.
This bar uses a bonding screw to bond the neutral bar to the earth ground that is connected to the panel via the ground bar.
Can I Combine The Neutral and Ground?
No, if there are two separate ground and neutral wires they should never be tied together.
This can be very dangerous. The neutral is there to carry any stray voltage safely back to the panel. If the ground is connected to it then it can energize the ground as well, creating a hazard.
Final Thoughts On Wiring 3-Prong 220 Outlets
Wiring up a 3-prong 220V plug doesn't have to be scary, as long as you take your time and respect what you are working on it can be a simple task. If homeowners have any doubts about the project, we highly recommend to at least consult with a professional electrician.
Safety is the most important thing, so make sure you have the power turned off before you begin your work. Take the time to look over what you have to ensure you have the right materials and you get it wired correctly.
If you have any doubts, questions, or are no longer feeling comfortable about working on it, be sure to give your local electrician a call to come and give you a hand!
I hope you enjoyed this Home Inspector Secrets guide!