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Polarized vs. Non-Polarized Electrical Plugs

Polarized vs. Non-Polarized Electrical Plugs

Have you ever compared the plugs on your electrical devices and wondered why there’s a difference? This is important element when building your own antique lamp and other DIY projects which involve plugs. Some of your electronic devices may have two identical prongs, two unequal sized prongs, or even three-prongs. While the three plug designs seem interchangeable, they differ in how they complete the electrical circuit from device to breaker panel.

Electrical Circuitry Explained

wiring-outlet-diagram

The simplest way to tell if your receptacle (electrical outlet) is polarized is if you are able to plug in a three-prong plug (NEMA 1-15 ground Type B) or if a two prong-plug (NEMA 1-15 ungrounded Type A) can only fit with the larger prong on the left. An electrical plug is designed to complete an electrical circuit from your home’s electrical panel to your electronic device and back. The hot, neutral, and ground wires are intended to complete the electrical circuit in a specific way as shown below.

  • Hot Wire: (Black wire) provides a path of 120 VAC (volts alternating current) electrical devices require to operate.
  • Neutral: (White wire) provides a return path for the current to electrical panel and is usually connected to an earth ground. 
  • Ground: (Bare or Green wire) is connected to a metal part of an appliance to provide a safety precaution in the instance the hot and neutral wire to come in contact with each other.

What is a Polarized Plug?

                          Polarized plug

                          Polarized plug

The two-prong plug of unequal size and the three-prong plug are polarized. In these cases, there is a clear distinction in which prong is designated for the “hot” side and the “neutral” side. By having the two different sized prongs or a three prong design, the electrical device can only be inserted into the electrical outlet/receptacle one way. The grounded wire (round prong), in a three-prong design are used as an extra safety precaution for electrical devices like a microwaves or coffee pots.

What is a Non-Polarized Plug?

                    Non-Polarized plug

                    Non-Polarized plug

Plugs with the two of the same-sized prongs are considered non-polarized because there is no clear distinction as to which prong is for the “hot” side and the “neutral” side. When older devices with a non-polarized two-prong design are inserted into a non-polarized outlet, the polarity (directional flow of the current) would be reversed. Reversed polarity leaves the circuit open and could potentially lead to electrical arcing or shocks. Thankfully, most receptacles in US homes today are polarized. For newer electronic devices, even though the two-prong design doesn’t feature a grounded wire, most non-polarized plugs are double-insulated as a safety precaution. That means that there are two layers of insulation between any live wires and any metal parts within the appliance to prevent electrical shocks and shorts from occurring.

Still have questions about electrical outlets or how to build your own antique fixture? Feel free to leave your question below in the comment section. For more information on electrical outlets, feel free to read our previous blog, “Can Your Electrical Outlets Protect Against a House Fire?” Be sure to check back on our blog for more articles about the wonders of lighting and electricity. Keep in touch with us through our social media pages via, Facebook, Twitter, Google+, LinkedIn, or Pinterest

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