For electrical beginners, understanding the differences between voltages is a common issue, and sometimes can be a very confusing task that can lead to endless debates.
Which one is better? 24-volt or 12-volt? Which one is safer between 120-volt and 240-volt? What do all those numbers even mean ?
In this article, we will discuss the differences between all the common voltages used in both DC and AC applications, and the advantages as well as disadvantages of each.
To understand the fundamentals of electrical voltage better, let's imagine that our wire is a water pipe, and the electrical current is the water current.
What then, is the electrical voltage in this water pipe assumptions? It is the water pressure inside the pipe. In fact, voltage is also often called electrical pressure or electrical tension. Check out this history of the term 'voltage' by Think For Yourself.
If we remember our junior high physics, pressure affects the speed of the water current entering the pipe. The harder the pressure, the slower the water speed, and the less water entering per any given time.
Understanding that basic principle, the higher the voltage, the less current will be entering the wire per any given time to achieve a certain power.
Thus, we came into the famous equation:
Where P is power, measured in Watts, kiloWatts, or megaWatts, I is the electric current measured in ampere, and V is voltage.
So, resuming our analogy of water, what changes as the voltage change?
In water, the higher the pressure, the more harmful it is to the human body. Is that the case with voltage? Apparently, yes, the higher the voltage, the more dangerous it will become when electrocution occurs.
In DC voltage applications, 12-volt and 24-volt are the one commonly used. 48-volt is a bit less common but is still widely applied in today's DC voltage applications.
On the other hand, in AC applications (the electricity supplied by the power company), 120-volt is the standard in U.S. and North America, while 240-volt is the standard for almost the rest of the world.
So, is the U.S. electricity safer than the rest of the world? And is 12-volt safer than 24-volt? The answer is a bit more complicated than that, so let's dig deeper.
We have discussed how generally lower voltage is safer during electrocution (safer doesn't mean entirely safe, reader's discretion is advised.) What other effects will a higher, or lower voltage bring to our electrical system as a whole?
Here are some notable ones:
So, in general, a higher voltage is more economical, while lower voltage is safer. However, these differences can extend differently within DC and AC applications, so let's divide the discussion into each of them. Let's start with DC first.
Although in DC applications more voltage rating are available, such as 48-volt, the principles should apply in a similar way. Thus, we will use 12-Volt and 24-Volt as the focus of the discussion.
The differences we will find between the two are:
In conclusion, a 24-Volt system will generally need more initial investment upfront, but will save more money in the long run.
Check out this video by DIY one for allfor a more thorough discussion about these two systems.
Moving on to the AC applications, what is it that made the U.S. use a different voltage than the rest of the world?
Can we take the same conclusion that 240-volt will be cheaper in the long run while 120-volt is safer? Well, yes and no. Let's delve further into that question.
North America's 120-Volt is actually a 240-Volt voltage divided into two. How did that happen? In our previous article about the history of the light bulbs, we have discussed that Thomas Alfa Edison was responsible for electrical distribution in the U.S., and he is certainly responsible for the 120-Volt choice.
Some claims that it might be that Edison's early light bulbs only work with 120-Volt voltage, but most Americans will say that the 120-Volt choice is because of the reason of safety. Check out this article fromWorld's Standards for further history lesson.
So, the basic principles we found on our previous discussion are still intact:
However, 120-Volt and 240-Volt is not a matter of choice, but rather the matter of where you live in. Problems may arise, however, when you are traveling to a country with different voltage rating than yours. What should you do with your devices and appliances then?
There are a few considerations you should make when you are traveling to different country, or when using a DC application with AC voltage:
Now that we understand voltage differences and associated effects, we can be more careful when traveling to another country, or deciding which voltage to use in our DC off grid system.
Nowadays, many appliances and lighting are manufactured to be able to operate in different voltages, certainly made life easier for us. However, make sure to check each of your device's voltage rating especially when traveling to other countries.
Comments will be approved before showing up.