Wiring a 3-prong plug with 2 wires is not very difficult, it’s an issue that electricians come across once in a while. You can complete the whole process in a few minutes. You do not even need any experience, and I am going to guide you through the entire process. If you find yourself in a situation where you have a 3-prong plug and two wires connected to an extension, and you want to tap power to the electrical extension, then this guide is for you.
You do not need to waste your money buying a new 3-prong plug extension; you can seamlessly connect two wires to the 3-prong plug and get power to your electrical extension, or any other device which is connected to the two wires.
Quick Summary: To wire a 3-prong plug with two wires, first, strip the terminals to expose the naked wire. But if the two wires are linked to a 2-prong plug or any other device, slice off the wires to detach them from the 2-prong plug. Next, unscrew the 3-prong plug to expose the positive and neutral pins, twist the terminals of the two wires, and screw them on the terminals – positive to positive, and neutral to neutral pins. Finally, cover up the 3-prong plug and tighten the cover. Restore your power supply and test your plug!
Safety Precautions
In any electrical wiring or renovations, the thumb rule is to cut off the power supply to the area you are working on. You can do that on the breaker unit.
Once you have turned off the power, you may use a voltage tester to be 100% sure that no power is flowing through the wires or the circuit that you are working on.
The next precaution is putting on protective gear. Protect your eyes with safety goggles. (1)
Once you have done all that, you can go ahead and start your wiring.
What Does Each Wire Do?
It is crucial to understand the polarities of the 3-prong plug pins. The wiring harness is as follows:
- Live pin
- Neutral pin
- Ground pin
The polarities of the pins are indicated in the diagram below:

Connecting the 3-prong Plug with Two Wires
After you have established the polarities of the 3-prong plug, and the power supply is cut off, you can begin connecting it with two wires. The detailed steps below will help you do that:
Step 1: Strip the Insulation Coating of the 2-wires

Using a stripper, remove the insulation layer to about ½ inch on the terminals of both wires. You can use pliers to do that. Note that if the two wires belong to a 2-prong plug, first cut out the plug header of the 2-prong plug before you strip the wires. (2)
Step 2: Unscrew the Plug
Unscrew the 3-prong plug including the wire binder, and remove its cover.

Step 3: Connect the Two Wires to the 3-prong Plug

First, twist the stripped ends of the two wires (not together) to make them compact. Now, insert the twisted ends into the screws of the 3-prong plug. Fasten the connection to the screws.
Note: The two terminals where you connect the two wires are neutral and live plugs/screws. The third plug is in the ground. In most cases, the wires are color-coded, and you can easily distinguish between neutral, hot, and ground wires.
Step 4: Restore the 3-prong Plug Cover

Finally, restore the 3-prong plug cover you removed during the installation of the two wires. Screw the cover into place. Test your new plug.
Take a look at some of our related articles below.
- How to crimp spark plug wires
- How to cap off electrical wires
- How to test a car ground wire with a multimeter
References
(1) safety goggles – https://www.rollingstone.com/product-recommendations/lifestyle/best-safety-glasses-goggles-1083929/
(2) insulation layer – https://www.sciencedirect.com/topics/
engineering/insulation-layer
Video Reference