Technical Description: Electrical Outlet

Keleni Alvarez

Writing For Engineering, B2

Professor Elizabeth Von Uhl

The City College of New York

April 6, 2023

Table of Contents

Table of Contents:

Introduction———————– pg.3

History—————————–pg. 3
External Overview———— pg. 4-5

 Terminals————————-pg. 6

Internals ———————— pg. 6-7
The Mechanisms—————pg. 7-8

 Conclusion———————– pg. 8

Reference Page.—————pg. 9-10

Introduction:

Electricity is one of the essential resources driving our society. It gives light to our cities and homes, gives us access to the internet, powers our devices, and saves lives. When electricity in homes started to become the norm, many concerns came from the fact that electricity itself is extremely dangerous and, when mishandled, can kill someone; so how exactly could people safely access electricity in their homes? In comes the electrical outlet. The electrical outlet is a device that allows your electronic devices to connect to the electrical grid and safely draw power. The electrical outlet was revolutionary because it offered a safe and convenient way to draw electricity while being extremely compact. When connected, the outlet will output an alternating current to the device, thus powering the device. For being some of the most common appliances found in almost any room, not enough people understand the many mechanisms that drive what, on the surface, appears to be a simple device.

 History:

At the turn of the 20^th century, the electrical outlet was the hottest thing to hit the electrical scene. Not only is it safe and compact, but it is also easy to use. The electrical outlet was invented in 1904 by Harvey Hubbell, an American Inventor who was mainly known for the outlet (Hubbell, 1906). Though they looked different back then, the outlet still functions similarly. A few years later, George P. Knapp would patent a three-pronged outlet on behalf of the Harvey Hubbell company, and it was at this point the outlet would start to take shape to become what it is today. The (Knapp, 1915) addition of a grounding line meant outlets became much safer; the grounding line neutralizes dangerous electrical currents and protects our devices from overvoltages and surges in electricity. When connected, the outlet will output an alternating current to the device, thus powering the device.

Figure 1 shows a diagram of the duplex outlet, detailing the exterior (Alvarez, K. March 28, 2023)

Exterior Overview:

Starting with the device’s exterior, we are examining a duplex outlet; this outlet is native to North America and is known as the type B outlet since it has two sets of three holes (USA – Power Plugs & Sockets: Travel Adapter Needed? n.d.). The white face plate of the outlet is made from plastic and is held in place with screws. At the top and bottom of the outlet, two mounting brackets ensure the outlet stays secure and level with the wall. The face plate has two vertical holes and one cylindrical hole. The two vertical holes correspond with the polarity of electricity. The right hole is known as the “Hot Side” because it is here where the electricity flows. The hole on the left is called the “Neutral side”; here, all the unused electricity is dumped into the ground, where it is neutralized. Lastly is the “Ground,” which is the cylindrical hole on the faceplate; the ground serves as an extra layer of protection. In the case of an overvoltage, all the dangerous electricity would be routed to the ground, where it would be neutralized without us knowing. Finally, the face plate is made of soft-touch plastic, and the back is made of plastic because it’s non-conductive.

  Figures 2 and 3 show detailed descriptions of the sides of the outlet (Alvarez K., March 28, 2023)

  Figure 2 (THIS IS THE LEFT SIDE).           Figure 3 (THIS IS THE RIGHT SIDE)

Terminals:

On the right side of the device, we will find the Line Terminal, Also known as the “Hot Side.” The Line Terminal is called the “hot side” because the electricity enters the outlet and the electrified wires are connected; you know this is the hot side because the two screws are typically made from brass with a golden yellow tint. In the US, electrical outlets supply up to 120 volts of electricity, which is enough to give you quite the shock, and sometimes only 50 volts are needed to be lethal (Metroid Electrical Engineering, 2022).

We will find the “Neutral Terminal” on the left side of the device. The Neutral Terminal is where the electricity exists in the outlet. Here, the non-electrified wires are connected; you know this is the neutral side because the two screws on this side are typically made from silver.

Also found on the left side of the device is the Grounding Screw; it’s a bypass to the rest of the electrical circuit, which directly connects the outlet to the ground, so unsafe electricity can be neutralized. You know which is the neutral screw because it is typically a singular green screw at the bottom of the outlet.

Internals

Looking under the hood, the outlet has no moving components, but it has elements that help the electricity move.                 

                                   (Figure 4 is a teardown of the electrical outlet)

                                                  This picture shows two main parts: the Outlet face plate and the “Receptacles.” Firstly, the faceplate protects us from the inside of the outlet and keeps us from inserting plugs incorrectly. It’s made from plastic which is non-conductive and safe to touch. Next, arguably the most complicated parts are the receptacles. There are two receptacles, and like before, the right side is for the hot side, the left is for the neutral side, and the middle hole is for the ground. The rest of the inside of outlet are supports for structural rigidity made from plastic.               

The Mechanisms                                                                                                        

figure 5 is a diagram of how electricity flows in a circuit 

(The Engineering Mindset, 2017)

One feature about each side is that there are no individual receptacles for the top and bottom; the top and bottom outlets share the same piece of metal per side. If you notice, there is only one piece of metal on each side of the device. When active, that whole side will become energized, from screws to receptacles.                              

A safety feature built into the outlet is that the face plate is made from thermoplastics meaning they don’t run or drip when on fire (Ray Franco – www.RayFranco.com, n.d.). The outlet can get the electricity working because the device you plug in is supposed to complete the circuit. Electricity will flow from points of higher, positive charge to points of lower, negative charge; this cyclical flow is called a circuit. If we look back at the picture of the electrical outlet, we have two sides, the Hot side and The Neutral side. When we complete the circuit, we complete the flow of electricity from high to low. Like the neutral side, the ground is also negatively charged.

Conclusion:

In conclusion, the electrical outlet is a marvel of modern technology and has marked itself as an innovation that has become essential to our everyday lives. A simple machine made of plastics and metal is driven by forces much greater than itself. With the outlet, we can quickly and safely harness the power of electricity. In about a hundred and twenty years since its creation, the outlet has powered our cities and devices and saved countless lives.

References:

 Different Types of Electrical Outlets and How They Work. (n.d.). Landmark. https://www.landmarkhw.com/resources/electrical/different-types-of-electrical-outlets-and-how-they-work/3/244#:~:text=A%20grounding%20wire%20is%20connected

Hubbell, H. (1906). Electrical specialities : catalogue and price list No. 9, August, 1906 / manufactured by Harvey Hubbell, Inc. : Harvey Hubbell, Inc. : Free Download, Borrow, and Streaming : Internet Archive. Internet Archive. https://archive.org/details/ElectricalSpecialitiesCatalogueAndPriceListNo.9August1906/page/n49/mode/2up

Knapp, G. P. (1915, January 11). US1179728A – Separable attachment-plug.        – Google Patents. https://patents.google.com/patent/US1179728

Metroid Electrical Engineering. (2022, August 17). Metroid Electrical Engineering – Switchboards – Fatal electric shock: what voltage causes death? –. https://www.metroid.net.au/engineering/knowledge_center/fatal-electric-shock-what-voltage-causes-death/#:~:text=The%20human%20body%20has%20an

Ray Franco – www.RayFranco.com. (n.d.). Electrical Receptacles. https://www.electrical-forensics.com/Receptacles/ElectricalReceptacles.html

The Engineering Mindset. (2017, October 18). How ELECTRICITY works – working principle [Video]. YouTube. https://www.youtube.com/watch?v=mc979OhitAg

USA – Power Plugs & Sockets: Travel Adapter Needed? (n.d.). POWER PLUGS AND SOCKETS OF THE WORLD. https://www.power-plugs-sockets.com/us/united-states-of-america/#:~:text=In%20the%20United%20States%20of%20America%20the%20power%20plug%20sockets,the%20frequency%20is%2060%20Hz.