What Does "Low Voltage" Actually Mean?

You’ve recently purchased a new device and you notice on the box that it says “low voltage.” We often hear of a number of people who are confused as to what this actually means: some suggest it uses less electricity and saves you money, while others say that means it’s safer to use. Those in the latter group are closer to correct; here is what “low voltage” really means.

Low voltage is a designation that indicates that something uses a lower stream of power than a traditional wall socket provides. Usually this means they come with some sort of a transformer or step-down device that reduces the voltage to a much lower level, which in turn means it’s much safer to use. Ultra-low voltage is even safer still, usually running at no more than roughly five volts or so, posing little risk of arcing and almost no risk of serious injury. This way if anything were to happen to cause a short in the device which deals an electrical shock, you’re not at risk for anything more than a small twinge of pain and maybe a singed hair or two.

Defining Low Voltage

The United States doesn’t actually have a threshold for “low voltage” per se, but it’s generally accepted that the maximum voltage for this level is considered to be around 50 volts. Conversely, anything greater than 600 volts is considered to be “high voltage.”

In the U.S., the standard wall socket runs at 120 volts, while the larger, round wall sockets that are usually found in your laundry closet to power your washer and electric dryer run 220 volts. However, both of these devices also carry a heavy risk for electrocution, serious injury, and possibly even death if exposed to the full current. “High voltage” areas have an even greater risk; imagine a major power substation, which can often carry voltage levels in the hundreds of thousands.

Why Use Low Voltage

If lower voltage is so much safer than high voltage, why run high voltage at all? The answer is sending low voltages over long distances is impossible. Every type of electric line loses voltage as you send the power over distance along a cable due to a factor known as “resistance.” The longer the distance, the more voltage you lose. AC voltage is less prone to this loss compared to DC voltage, which is why it’s used in most homes.

Therefore, sending electricity along lines over hundreds of miles requires hundreds of thousands of volts, whereas voltage from your wall socket to your new television can comfortably sit at 120, and even then your TV will likely transform the current down to a lower level in order to run off an even, consistent power current.