Why is the Standard Voltage in US homes 120V & 240V but 230V in the EU? Why Not Other Higher or Lower Levels of Voltage?
The standard household voltage level in US homes is 120V AC- single phase. While the 120V is used for lighter loads, 240V split phase voltage is also commonly available for higher loads. It means, mostly both 120V and 240V is available from a main panel. While the rest of the world, especially the IEC following countries in the EU and UK, uses 230V while some of them like AUS etc. uses between 220V – 240V as a standard single phase voltage for domestic and commercial applications.
- Good to Know: Taiwan & Japan use only one level of 100V to 127V single phase AC power.
In today’s post, we will discuss the selection and standardization of 120V, 240V, and 230V, which are commonly used voltage levels in the US, EU, and UK, respectively, rather than higher or lower voltage levels
- Chart List of Standard Voltage and Frequency Around the World
- Difference Between 120V and 240V/230V AC Power Supply
Standardizing of Household Voltage of 120V in the US
The standard household voltage in the United States is 120V, but have you ever wondered why this voltage was chosen? Understanding the history and reasons behind this decision can provide valuable insights into the electrical system that powers our homes.
The choice of 120V as the standard voltage can be traced back to the late 19th century when electricity was first being introduced for commercial and residential use. During this time, two different electrical systems were in use: direct current (DC) and alternating current (AC).
At that time, the War of Currents was raging between proponents of DC and AC, with each side advocating for their own system. However, it was ultimately the AC system that prevailed, thanks in large part to the efforts of inventor Nikola Tesla and businessman George Westinghouse.
One of the reasons AC won out was that it allowed for the use of transformers to increase or decrease voltage levels. This meant that electricity could be transmitted over long distances with less power loss, making it a more efficient system overall.
In the early days of the AC system, various voltages were used in different parts of the country. However, in the 1920s, the National Electrical Manufacturers Association (NEMA) established 120V as the standard voltage for residential and commercial use. This decision was based on several factors, including safety, convenience, and practicality.
One reason for the choice of 120V was safety. At the time, electrical insulation and protection were not as advanced as they are today. By using a lower voltage, the risk of electrocution and other electrical hazards was reduced.
Another factor was convenience. Many electrical devices and appliances had already been designed to operate at 110-120V, so adopting this voltage as the standard made it easier for consumers to use and replace their devices.
Finally, practicality was also a consideration. At 120V, the transmission and distribution of electricity was still relatively efficient, while also providing sufficient power for most household needs.
Since then, 120V has remained the standard voltage for residential and commercial use in the US, with very few exceptions. The only major exception is in certain parts of the country, where 240V is used for large appliances such as stoves, dryers, and air conditioners.
The choice of 120V as the standard household voltage in the United States was based on a combination of safety, convenience, and practicality. While there have been advances in electrical technology and safety since then, 120V remains the standard and is likely to continue as such for the foreseeable future.
Selection of 240V in the US & Canada
The standard household voltage in the United States is 120V, but in some parts of the country, 240V is used for large appliances such as stoves, dryers, and air conditioners. In this article, we will explore the selection and standardization of 240V in the US and why it is used for specific applications.
240V is a higher voltage than 120V, and it is typically used for appliances that require more power to operate. The decision to use 240V for these applications was based on several factors, including efficiency, safety, and practicality.
One of the main reasons for the use of 240V is efficiency. Appliances that require more power to operate, such as stoves and dryers, can be run more efficiently at 240V. This is because the higher voltage allows for the use of smaller wires and circuits, which results in less power loss over long distances. Additionally, appliances that operate on 240V tend to have faster heating times and can complete their tasks more quickly.
Another factor in the selection and standardization of 240V was safety. Using a higher voltage means that less current is needed to achieve the same amount of power, which can reduce the risk of electric shock. Additionally, the use of 240V for large appliances means that a separate circuit is required, which can reduce the risk of overloading circuits and causing electrical fires.
Practicality was also a consideration in the selection and standardization of 240V. Appliances that require more power to operate, such as stoves and dryers, have been designed to operate at 240V for many years. This means that the use of 240V for these applications is well-established and understood, making it a practical and reliable choice.
In terms of standardization, the use of 240V for large appliances is not universal in the US. In some parts of the country, 208V or 220V may be used instead. However, these voltages are still higher than the standard household voltage of 120V and are used for the same reasons as 240V: efficiency, safety, and practicality.
The selection and standardization of 240V in the US was based on factors such as efficiency, safety, and practicality. By using a higher voltage for large appliances, power can be transmitted more efficiently, while also reducing the risk of electric shock and overloading circuits. While 240V is not the standard household voltage in the US, it is still an important part of the electrical system that powers our homes and appliances.
Selection and Standardizing of 230V in the UK, EU & IEC Following Countries
The standard household voltage in the United Kingdom and the European Union is 230V, and this has been the case for several decades. In this article, we will explore why this voltage was selected and standardized, and how it is used in homes and businesses throughout the region.
The selection of 230V as the standard household voltage in the UK and EU was based on several factors, including safety, efficiency, and compatibility with other countries. Before the introduction of the standard, voltages in different countries varied widely, with some countries like US using 120V or 240V. In the UK and EU, the decision was made to standardize on 230V in order to ensure safety and consistency across the region.
One of the main reasons for the selection of 230V was safety. Lower voltages can be more dangerous because they require higher currents to deliver the same amount of power, which can increase the risk of electrical shock. By selecting a higher voltage such as 230V, less current is required to deliver the same amount of power, which can reduce the risk of electrical shock and make electrical systems safer for people to use.
Efficiency was also a consideration in the selection of 230V. Higher voltages allow for the use of smaller wires and components, which can reduce costs and increase efficiency. By selecting a higher voltage such as 230V, electrical systems can be designed to use smaller wires and components, which can lead to cost savings and improved performance.
Compatibility with other countries was also a factor in the selection of 230V. Many countries around the world use a voltage of 220V or 240V, and by selecting a voltage of 230V, electrical systems in the UK and EU can be designed to be compatible with these other countries. This can be important for international trade and travel, as it reduces the need for voltage converters and other devices that can add complexity and cost to electrical systems.
In terms of standardization, the use of 230V is universal throughout the UK and EU. This means that all electrical devices and systems in these regions are designed to operate at this voltage, which ensures safety and compatibility across the region. In addition, the use of 230V has become an important part of the electrical infrastructure throughout the UK and EU, and is used to power homes, businesses, and other buildings throughout the region.
The selection and standardization of 230V as the standard household voltage in the UK and EU was based on several factors, including safety, efficiency, and compatibility with other countries. By using a higher voltage, electrical systems can be designed to be more efficient and safer, while also being compatible with other countries around the world. The use of 230V has become an important part of the electrical infrastructure throughout the region, and will continue to be used for years to come.
Why Only 120V, 240V, and 230v in the the US and EU? Why Not Other Higher or Lower Levels of Voltage?
In the 1870s to 1890s, Thomas Edison developed the 110V DC current and created a three-wire power distribution system. He also used a configuration of two 110V wires and a neutral wire to form a 220V DC system. Later on, Nikola Tesla adopted 110V AC for lighter loads, such as incandescent lamps, and 220V AC for larger load applications.
At the end of the 19th century, a large number of electrical appliances and machines were introduced in the US market and adopted by homes and businesses. This necessitated a standard voltage level for different applications. As a result, the 120V and 240V system was standardized in 1967, replacing the earlier 110V, 115V, and 220V systems.
In 1891, the era of DC power came to an end when the three-phase AC power was introduced and launched at a commercial base during the Electro-Technical Exposition in Frankfurt, Germany.
To improve power transmission and distribution efficiency, the EU migrated to the 220-240V power supply system from the early, originally established 120V power system. The US also considered migrating but ultimately decided to remain on 120V while adding an additional split-phase 240V supply voltage. Modifying the existing and well-established infrastructure to the new design and configuration would have been costly. To avoid this hassle and lengthy but expensive migration, the US chose to add an additional split-phase 240V supply voltage. This is why US homes now have both 240V and 120V AC power.
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