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Plug-ins power our everyday electrical devices. Some plugs have two prongs, while others have three. So what is the third prong in the plug for?

The third prong is a grounding safety feature that protects from malfunctions. In fact, based on an estimate by the Consumer Product Safety Commission, Ground Fault Circuit Interrupters, or GFCIs, have prevented 50% of home electrocutions.  

Let’s explore how three-prong plugs work and what they do in our electrical systems. 

What Does the Third Prong on a Plug Do?

Most North American outlets have two vertical slots. The hot wire is the right slot, and the left is the neutral wire. First, electricity travels through the hot wire to power your device. Then, the current continues by returning to the outlet through the neutral wire. 

Without this loop, the circuit would be incomplete. In other words, for an outlet or device to function, you only need two prongs.

The rounded third prong on a plug is a ground prong or grounding wire. Electricity is always looking for a path to the ground. If damage or a malfunction occurs, altering the circuit, the ground wire is an emergency path that protects you and your devices from electric shock.

In a two-prong outlet, a loose wire or malfunction might cause the electrical current to connect with the outer parts of the device or outlet. Two-prong plugs are insulated, but the outer layers can wear down over time or with continuous use.

Third Prong FAQs

three prong extension cord up close

Here are some commonly asked questions about the three-prong plug.

Is it safe to use a “cheater plug” or remove the third prong?

If you have a three-pronged plug, it will only fit into three-prong outlets. However, you can’t cut off the third prong, as it completes the ground circuit. It’s a crucial safety feature that protects against faults.

Cheater plugs or AC ground lifters adapters that allow three-pronged plug devices to function with a two-pronged outlet. However, it doesn’t complete the grounding circuit. The outlet will power your device, but it is a temporary solution that removes the safety feature. 

What can I do for outlets with only two prongs?

Suppose the device you want to use has a three-prong plug, but you only have access to a two-prong outlet. An adapter is a helpful short-term fix, but it shouldn’t support long-term uses or outdoor devices. Alternatively, an electrician can upgrade your ungrounded outlets into three-prong outlets.

Why do some electronics have only two prongs?

Some devices have built-in surge protection without a ground prong. It’s a necessary safety feature when using a two-prong or ungrounded outlet. Instead of a ground wire, these devices use an internal voltage adapter or insulation that protects the device from a short circuit. 

The holes that appear in 98% of appliances with flat two-prong plugs are not for grounding. They are a safety feature that grips inside the socket to prevent slipping.

Why do some plugs have a third prong?

The added safety of 3-prong plugs is crucial for any appliance or cable intended for outdoor or wet area usage. Moisture and external factors can wear on plugs and lead to hazardous malfunctions. 

Ungrounded outlets or plugs are more likely to suffer malfunctions, flare-ups, and electrical fires.

Are Plug Adapters Safe?

extension cord plugged into a plug adapter

Adapters are not as safe as grounded three-prong plugs or surge-protected two-prong devices. Although, while not inherently dangerous, adapters can be a risk in some cases. 

Do not use adapters for: 

  • Ungrounded outlets: old outlets that lack a ground wire are a leading cause of electrical house fires)
  • Major appliances that use significant power (oven, fridge, etc.)
  • Devices with metal housing (toaster, kettle, etc.)
  • Plastic outlet wall boxes. While plastic outlet wall boxes are non-conductive, their shape can distort or melt, worsening when an error or surge occurs.


If you’re unsure about the grounding of your outlets, it’s wise to get your electrical system assessed. You can also upgrade your two-prong outlets to three-prong outlets with the help of our professional electricians in Richmond, VA.

Contact U.S. Electric to assess your electrical system and make changes or upgrades. Call us now for a free quote!