A How-To Guide on Fluorescent Light Ballast Replacements (2024)

FAQs

A How-To Guide on Fluorescent Light Ballast Replacements? ›

T8 = 1-inch diameter. T12 = 1-1/2-inch diameter.

T8 = 1-inch diameter. T12 = 1-1/2-inch diameter.

When a ballast starts failing, it will typically buzz or causes the bulbs to flicker. These issues can sometimes happen while it is operating as expected, so it's important to check the equipment before assuming a replacement is necessary.

Type A operates on fluorescent ballasts, Type B is direct wired to the mains with the ballast or driver being located inside the tube, and Type C operates on its own dedicated external LED driver.

Understanding Tube Sizes

If T8 and T12 are using the same bi-pin base (G13 most commonly), then you can use the bulbs interchangeably using the same fixture just as long as you check the milliamp requirements for the ballast (if applicable).

Simply turn the light on, then take a photo of the fixture using your smartphone or digital camera. If there are no dark bands on the resulting image, you have an electronic ballast that is likely to work with direct drop-in LED tubes (with caveats: see the next section below).

Replacing a ballast is different than replacing a light fixture. However, buying a ballast can be expensive, so consider pricing a brand-new fixture for comparison. You can find a new ballast at a hardware store or home center and install it in about 10 minutes.

The most common types are T12, T8, and T5. The T stands for tubular and the number indicates the diameter in 1/8 of an inch. Lamp diameter is determined by ballast type. A fixture with a T12 ballast must use a T12 bulb.

T8 LED lamps which are not direct-wire compatible (with ballast) will require a T8 ballast to operate, so unless the T12 ballast in the T12 fixture is replaced with a T8 ballast, a non-direct-wire compatible T8 LED lamp will not work in a T12 fixture.

You can as long as you also replace the T12 lamps with T8 lamps. T12 lamps are of a higher wattage than T8 lamps so you risk shortening the lifespan of the ballast if the wrong lamps are used.

What does T8 mean on a ballast? ›

Specifically, the term "T8" indicates that the fixture is designed for T8 lamps, which are a specific lamp size (1 inch diameter).

The average life expectancy of a fluorescent light ballast is 10-15 years. Any ballast beyond that age should be considered to be at a heightened risk of failure.

Flickering fluorescent tubes can cause the ballast to overheat and fail prematurely! Causes of Ballast Failure: Premature ballast failure is usually caused by the surrounding environment. Heat and moisture are enemies #1 and #2 to your ballast.

Fluorescent lamps and HID (high intensity discharge) light bulbs do require a ballast. Both lamp families use two different types of ballasts: magnetic and electronic. Magnetic ballasts use older technology but are still used with certain light bulbs. Electronic ballasts are generally more energy efficient.

Pick the wrong T8 ballast and a system may not operate as envisioned — lamps could require frequent replacement or light output might not match projections. Matching lamps with the proper ballasts is especially important when occupancy sensors are used.

The good news is that a typical ballast will generally last about 20 years, so you won't have to worry about replacing them very often. However, cold environments and bad bulbs can factor into the mix, causing the lifespan of the ballast to decrease significantly.