What is a Light Ballast?


Every industry has its own jargon and terminology. And it’s usually only those who have training or experience in that industry who can understand what’s going on if the conversation starts heading in that direction. Electricians and those in the electrical trade easily fall under that umbrella, with a whole collection of words and phrases that only they seem to understand or are able to speak about.

But no matter who you are, it’s helpful to know certain terms and their meanings, especially when it comes to electricity. Even though we might not think of it that often, electricity is something that affects us all, at practically every moment of every day.

One common term that people have often heard but don’t often know its meaning is “light ballast”. Perhaps you’re in the boat of recognizing the term but unsure of its exact meaning. Well, let us shine some light on the topic. (Shine some light… get it?!)

A light ballast is a component of fluorescent lighting. In a fluorescent lighting system, the light ballast serves two purposes: to regulate the current to the lamp, and to provide enough voltage to start the lamp.

In other words, once a lamp turns on, an arc between the two lamp electrodes needs to be produced. In order for this to happen, the ballast needs to mediate a high voltage and distribute it.

In the moment that the lamp starts or is turned on, the ballast must briefly supply a high voltage in order to establish an arc between the two lamp electrodes. And then once the arc is established, the ballast quickly reduces the voltage and regulates the electric current to produce a steady light output.

What would happen without a ballast?

If a light ballast weren’t in place, the fluorescent lamp would uncontrollably increase the amount of current it draws from the power source. Within a second, the lamp would overheat and burn out.

How do you know your ballast is functioning properly?

As mentioned, if the ballast is completely defunct, the lamp will burn out almost instantly. Under optimal conditions, light ballasts do tend to last a long time, up to 20 years or so. However, if they are constantly exposed to cold air or poor quality light bulbs can decrease the life span of a light ballast. If your fluorescent lights are flickering or humming, it is worth checking to see if the light ballast is functioning properly.

How do you know what light ballast to buy?

There are plenty to choose from so the best thing is to ask a professional, either at the hardware store or by consulting your electrical technician. If you are planning on replacing the ballast at your home or office, make sure you have the specific information of the light fixture you are working with. In order for the ballast to be compatible, it must precisely match the electrical requirements of the lamps it operates.

And there you have it. Now you can impress anyone at your next dinner party by talking about light ballasts like a pro!

We hope this information helps and if you have any questions about indoor or outdoor light installations or anything electrical, our experienced staff is happy to help.