How Does a 3-Pin Plug Work?


When you insert a plug into an outlet in your house, you connect directly to the plant that generates the electricity you use, via a line transformer and a panel. It only takes two pins to do this. The third pin on some plugs grounds the circuit and prevents shocks and fires.

Two-Pin Plugs

  • The alternating current provided by the power company passes between two live, or "hot", wires in the panel, with a total of 240 volts between them. When an electrician wires a receptacle, he does it with one of these hot wires and a neutral wire that returns to the transformer to complete the circuit. This creates a 120-volt circuit. When you insert a two-pin plug, one pin connects to the hot wire and one connects to the neutral to extend the circuit through the wire to which the plug is attached.

Adding a Third Pin

  • During the installation of an electrical system, the electrician grounds the panel with a metal rod or some other means that provides a pathway for electricity to disperse into the earth. He connects each electrical device on the circuit, including all receptacles, to this ground path with a separate wire. Proper grounding prevents the build-up of charge on poorly insulated devices that can cause shocks and start fires. The third pin on a plug connects the plug to this ground path.

Related Searches


  • Photo Credit suzanneblakely/iStock/Getty Images
Promoted By Zergnet


You May Also Like

Related Searches

Check It Out

How to Build and Grow a Salad Garden On Your Balcony

Is DIY in your DNA? Become part of our maker community.
Submit Your Work!