Replacing Fluorescent Light Bulbs With LED Tubes: Getting Rid of the Ballast

If you have fluorescent lights in your garage, shop, office, or just about anywhere else, chances are you have dealt with a burned-out bulb at some point. You pull the old tube out, take it to the hardware store, buy another one that looks the same, and put it back in. Problem solved.

Or maybe not.

Sometimes the new bulb flickers. Sometimes it takes a while to come on. Sometimes the light just quits working even though you know you installed a new bulb. When that happens, the problem may not be the bulb at all. It might be the ballast.

The good news is that there is another option. You can replace those old fluorescent tubes with LED tubes that fit the same basic fixture and do not require the original ballast. This is commonly called a ballast-bypass retrofit, and it can be a great way to simplify your lighting while reducing energy consumption and future maintenance.

Let's look at what is involved and why it might be worth doing.

What Exactly Does a Fluorescent Ballast Do?

A fluorescent light is a little different from an ordinary incandescent bulb. You cannot simply connect a fluorescent tube directly to household power and expect it to work properly. The fixture needs a ballast to regulate the electrical current and help the lamp start.

The ballast is usually a rectangular metal box mounted inside the light fixture, behind the cover that holds the wiring. If you have ever removed the cover from an old fluorescent fixture, you have probably seen one.

The ballast is an additional electrical component that can eventually wear out. Depending on the type and condition of the ballast, you might experience flickering, humming, delayed starting, or a light that refuses to turn on.

When that happens, you have a few choices. You can replace the ballast, replace the entire fixture, or convert the fixture to use LED tubes that operate without it.

For many existing fixtures, that third option is worth considering.

What Is Different About an LED Tube?

One of the nice things about LED technology is that LED tubes are available in familiar shapes and sizes. For example, many common four-foot T8 LED tubes have the same general form factor and pin arrangement as the fluorescent tubes they replace.

But there is an important distinction: not all LED tubes work the same way.

Some LED tubes are designed to operate using a compatible existing fluorescent ballast. These are commonly called Type A or plug-and-play tubes. They are convenient because you can leave the fixture wiring alone, but the ballast remains part of the system.

Other LED tubes are designed to operate directly from the electrical supply. These are commonly called Type B or ballast-bypass tubes.

With a Type B tube, the ballast is removed from the operating circuit, and the fixture is rewired according to the LED manufacturer's instructions. The LED tube has the electronics it needs to operate without relying on the old fluorescent ballast.

That is the big difference. You are not simply replacing one kind of bulb with another. You are changing how the fixture supplies power to the lamp.

Why Bother Bypassing the Ballast?

The biggest reason is simplicity.

Once the conversion is completed correctly, there is one less component in the fixture that can fail. You no longer have to worry about replacing the original fluorescent ballast when it eventually stops working.

There are several potential advantages:

Lower energy consumption. LED tubes can provide comparable light output while using less electricity than many fluorescent systems. Actual savings depend on the original lamps, ballast losses, and the replacement LED's wattage.
Less maintenance. Removing the ballast from the operating circuit eliminates that component as a future maintenance item.
Quick starting. LED tubes generally come on immediately rather than relying on the starting behavior of a fluorescent system.
Different light color options. Depending on the product, you can choose warm white, neutral white, cool white, or daylight-colored illumination.
A familiar fixture. You may be able to keep the existing fixture housing instead of replacing the entire light.

Of course, none of this means every old fluorescent fixture should automatically be converted. If the fixture is badly corroded, damaged, or poorly constructed, replacing it with a new LED fixture may be the better choice.

Make Sure You Buy the Correct LED Tube

This is where it pays to slow down and read the label.

A tube that looks identical to the old fluorescent lamp is not necessarily electrically compatible with your fixture. Tube length and pin spacing are only part of the equation.

Before buying anything, identify the existing lamp type and check the replacement manufacturer's specifications.

For example, a T8 tube and a T12 tube may share the same common G13 bi-pin base, but that does not automatically make every LED replacement suitable for every fixture. You also need to consider the intended wiring configuration, lamp-holder type, supply voltage, and any special features in the fixture.

Pay attention to whether the replacement is:

Type A: Designed for a compatible ballast.
Type B: Designed for ballast-bypass operation.
Type A/B: A hybrid lamp approved for both compatible-ballast and ballast-bypass installations.

If your goal is to eliminate the ballast, a Type B tube is the straightforward category to investigate. A Type A/B tube may also work, provided you configure the fixture according to the manufacturer's instructions for ballast-bypass operation.

Do not assume that every tube labeled LED is designed for direct wiring.

What Does the Conversion Involve?

The basic idea is fairly simple, although the actual wiring depends on the particular LED tube and fixture.

First, the electrical power to the fixture must be disconnected at the breaker. Turning off the wall switch alone is not enough. The installer must verify that the wiring is de-energized before opening the fixture or touching its electrical connections.

The fluorescent tubes are then removed, followed by the fixture cover that protects the ballast and wiring.

The ballast is disconnected from the circuit and either removed or otherwise isolated as specified by the retrofit instructions. The incoming electrical supply is then connected to the appropriate lamp holders using the exact wiring configuration required by the selected LED tube.

This last part is especially important.

Some ballast-bypass LED tubes use a single-ended design, where line and neutral connect at the same end of the tube. Others use a double-ended design, where line and neutral are supplied at opposite ends. These arrangements are not interchangeable, and the correct wiring also depends on the lamp holders and fixture configuration.

Simply cutting the ballast out and connecting wires without following the correct diagram is not a good idea.

If you are unfamiliar with electrical wiring, have a qualified electrician perform the conversion. The work must comply with applicable electrical codes and the lamp manufacturer's instructions.

Once the wiring is complete, the fixture is reassembled, the appropriate retrofit identification label is installed, and the system is tested according to the manufacturer's instructions.

What About the Old Ballast?

Once the fixture has been converted properly, the original ballast is no longer needed for the operation of the LED tube.

Depending on the fixture and the approved retrofit method, the ballast may be removed entirely. The important thing is that it must not remain connected in a way that conflicts with the new lamp's wiring requirements.

There is also a practical reason to label the fixture after the conversion.

Someone working on the light in the future might assume it still contains ordinary fluorescent tubes. If they install a fluorescent tube into a fixture that has been rewired for direct-line LED operation, the results could be dangerous.

A suitable ballast-bypass retrofit label helps communicate that the fixture has been modified and that only the appropriate replacement lamps should be used.

Keep the installation documentation, too. It can save time the next time a lamp needs replacing.

Is It Really Worth the Effort?

That depends on how many fixtures you have, how much they are used, and the condition of the existing equipment.

If you have one fluorescent light in a storage room that gets switched on once a month, the financial payback might not be especially exciting.

On the other hand, if you have a garage, workshop, warehouse, or office with dozens of fluorescent tubes running for several hours every day, the potential savings can add up.

Here is a simple way to estimate the energy savings.

Suppose an existing fluorescent lamp and its share of the ballast losses consume 40 watts, while the replacement LED tube consumes 18 watts.

The difference is 22 watts per lamp.

For ten lamps operating eight hours per day over 250 days per year, the annual energy savings would be:

10 lamps × 22 watts × 8 hours × 250 days = 440,000 watt-hours.

That works out to 440 kilowatt-hours per year.

Multiply that number by your electricity rate to estimate the annual energy-cost savings. At an illustrative rate of $0.20 per kilowatt-hour, that would be $88 per year.

Your actual savings will depend on the original fixture's consumption, the LED wattage, operating hours, electricity rate, and the cost of the retrofit.

There is also the maintenance side of the equation. If the old ballasts are already failing, eliminating them may save you the cost and inconvenience of replacing them later.

A Few Things to Remember

Before you start replacing fluorescent tubes throughout an entire building, there are a few things worth keeping in mind.

First, verify that the replacement LED tube is approved for the intended fixture and installation method. Second, pay attention to light output, not just wattage. A lower-wattage lamp is not necessarily a suitable replacement if it does not provide enough illumination.

Third, check whether the fixture has special features, such as emergency lighting, dimming controls, or occupancy sensors. These systems can affect which LED products and retrofit methods are appropriate.

Finally, fluorescent lamps may contain mercury. Handle old tubes carefully and dispose of them according to applicable local requirements rather than assuming they belong in ordinary household trash.

The Bottom Line

Replacing fluorescent tubes with LED tubes that do not require a ballast can be a practical upgrade. You can retain a suitable existing fixture, reduce electricity consumption, and eliminate the original ballast as a future point of failure.

The key is understanding that a ballast-bypass LED tube is not simply a different bulb. It is part of a different electrical arrangement.

Choose the right tube, follow the manufacturer's wiring instructions, make sure the work is performed safely, and label the converted fixture for future maintenance.

Do it correctly, and the next time an LED tube burns out, replacing it should be a much simpler job. You will not have to wonder whether an old fluorescent ballast is the reason your light stopped working.

Sometimes the best upgrade is not replacing everything. It is getting rid of the one component you no longer need.

Shawn Kernes Blog