How to Install and Replace Fluorescent Tube Lights

March 4, 2021April 2, 2022 by Peter In Home Improvement 1 Comment

Before moving into our house, the only time I had seen fluorescent tube lighting was in businesses and office cubicles. Curiously, our house not only has fluorescent tube lighting, but two different types! When one of these lights burned out, I had to learn all about them to replace the tube. If you’re in this same situation, here’s a step-by-step guide to installing and replacing fluorescent tube lights.

Reading Tube Light Product Information

Replacing a tube light is not as easy as replacing a standard 60 Watt light bulb. Tube lights come in all sorts of different sizes and types. In order to know which one you have, you need to understand the product information stamped on the tube light. Here are two examples from the tube lights in our house:

Product information stamp for a U-Bend tube light.

Product information stamp for a linear tube light.

Tube light product data is separated by a forward slash (the “/” symbol). So you can notice the Philips light reads “FB40T12 / CW Supreme” and the Sylvania light reads “F40T12 / CWX”. The forward slash separates two important data categories: Type, Wattage, and Size and Light Color. Let’s break these down:

Type, Wattage, and Size

Type: The letter F or letters FB refer to the type of light, and simply stand for Fluorescent or Fluorescent Bulb.

Wattage: The number following the F or FB is the wattage. For both examples shown, the number 40 follows. This means that the tube light is 40 Watts. This is so important that both manufacturers have repeated this information by explicitly writing 40 Watt or 40W elsewhere on the product information stamp.

Size: Finally, a T12 follows the wattage number. The T stands for Tube, and the number 12 that follows is the tube diameter. Tube lights typically come in three common sizes: T5, T8, and T12. The number that follows the T expresses a diameter in eighths of an inch. So a T5 corresponds to a tube diameter of 5/8 inch, a T8 is 8/8 or 1 inch, and a T12 is 12/8 or 1.5 inches.

Light Color

The light emitted by a light bulb has a certain color, and this color is defined by a Kelvin rating. A value of around 2,700 K produces a yellowish color, often described as “warm.” A value of around 4,000K produces a bright white color, often described as “cool white.”

For both examples shown, the letters CW are in the Light Color data field, indicating that these tube lights are “cool white” in color.

Linear Tube Lights

This is probably the most common type of fluorescent tube light – a long, straight tube. They’re also the trickiest to install or remove if you’ve never done it before. The ones in our house are 48 inches long, and have two pins (called bi-pin) at the ends that look like this:

Bi-pin end of a tube light — A bi-pin end of a tube light.

The linear, bi-pin tube light fits into a socket that looks like this:

Socket for a linear bi-pin tube light — Socket for a linear, bi-pin tube light.

Installing and Removing a Linear Tube Light

To install a linear, bi-pin tube light, you (1) insert both pins into the socket, then (2) rotate the tube light (in either the upward or downward direction) until it locks into place. You will need to do this for both ends of the tube light, which can be a bit of a balancing act – another pair of helping hands can make things much easier!

To remove a linear, bi-pin tube light, you reverse the steps: (1) rotate the tube light (in either the upward or downward direction) until it unlocks, then (2) remove both pins from the socket.

This picture illustrates the steps to install and remove a linear, bi-pin tube light: