The electric cable that runs to the 120-volt outlets and other fixtures in your home has three wires inside the plastic sheathing: a hot wire (the “live” wire that brings the electricity in), a neutral wire (the one that routes the electricity back to the electric panel and completes the circuit), and a ground wire. The ground provides a safe, alternate route for electricity if it goes astray—perhaps because a hot wire has come loose at a connection or become frayed, and then comes in contact with the metal casing of a power tool or cabinet of a refrigerator, for example. Those parts are connected to the ground wire of the cord of the appliance and will complete a circuit whenever they become electrified. 

   Because the ground wire offers minimal resistance to the current flow, a surge of electricity will flow through it and trip a circuit breaker (or blow a fuse) in your electric panel and alert you to a problem. Without the ground wire connection, an electrically charged surface would do nothing, until you touch it while in contact with the ground or a grounded object, completing a circuit that would shock and possibly electrocute you.

   A ground wire is bare (no insulation) or green. Electric outlets/receptacles have been required to have that third, round ground slot that connects to a ground wire since the early 1960s. 

    Also, see our blog post Why is it unsafe to bond neutral and ground wiring at subpanels?

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Here’s links to a collection of our other blog posts about ELECTRICAL WIRING:

• Which house appliances need a dedicated electrical circuit?

• Can a short circuit cause a high electric bill?

• What is the maximum spacing requirement for securing NM-cable (nonmetallic-sheathed cable)?

• Is it alright to just put wire nuts on the end of unused or abandoned NM-cable or wiring?

• What causes copper wires to turn green or black in an electric panel?  

• What are typical aluminum service entrance wire/cable sizes for the electrical service to a house?

• Why is it unsafe to bond neutral and ground wiring at subpanels?

• Should I get a lightning rod system to protect my house?

• Why is a strain relief clamp necessary for the cord connection to some electric appliances?  

• What is an open electrical splice?

• What are the most common electrical defects found in a home inspection? 

• What is the life expectancy of electrical wiring in a house? 

• What is an "open junction box"? 

• How dangerous is old electrical wiring? 

• What is a ground wire? 

• I heard that aluminum wiring is bad. How do you check for aluminum wiring? 

• What is "knob and tube" wiring?

    Visit our ELECTRICAL page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.