Which Linear Fluorescent Tube Do I Need

In our brick and mortar location and our website, we consistently see customers that are confused over which fluorescent bulb they need to replace a defective bulb in their home or workplace. There are thousands of different fluorescent bulbs from many many manufacturers. Getting the right bulb for your application can be difficult. Let's see if we can help.

The easiest and most fool proof way to identify a fluorescent lamp is to get the catalog number off the bulb itself. In the vast majority of cases the catalog number of a linear fluorescent tube the catalog number begins with an "F" (ie F20T12/CW, F96T12/D, F32T8/841, F54T5HO/835). Different manufacturers give the same bulb a different catalog number. These numbers mean something to people in the lighting business. However, since the numbering system is archaic, explaining the system to someone who doesn't use it on a regular basic is difficult. Despite, having different catalog numbers, there is a lot of interchangeability between manufacturer's catalog numbers. A lighting professional can help identify a lamp that will work in your application, if you have the catalog number.

If your fluorescent tube is broken or does not have a catalog number etched on it, a different method will have to be used to identify the fluorescent lamp required. First thing to do is measure the length of the fluorescent tube. Fluorescent bulbs are measured including the pins (base) that hold the lamp in the sockets (tombstones). If your fluorescent tube is broken, measure between the sockets that hold the bulb in place. Then add a bit for the pins.

The next bit of information you will need is the diameter of the bulb. Fluorescent tubes come in different diameters, from  a T5 (5/8"), T8 (1"), T12 (1.5}), up to a T17 (2-1/8). There are other diameters on the market, but these cover the majority of fluorescent tubes. If your fluorescent tube is broken, a different method will have to be used to narrow the diameter down. More on that later in this article.

The next piece of information needed is the configuration of the base (the pins, etc. that hold the bulb in the socket). The most common are: miniature bipin (T5 lamps), medium bipin ( T8 and T12 lamps, single pin (some T12 lamps), and recessed dual contact ( HO & VHO T12 bulbs). If the lamp is broken, inspect the sockets and get familiar with what they look like and this will go a long way to helping you identify the lamp you need. If necessary use the camera in your phone, and show this to or email to someone in the lighting business. Also, this will help determine the diameter of the bulb. A word of caution, just because a fluorescent tube's length and diameter is known, the base configuration needs to be determined, many lamps have the same length, but not the same base.

The next piece of information needed is the color of the light the fluorescent tube produces. Some of the more common colors a cool white, daylight, warm white, etc. Many of the new fluorescent lamps produced in the past 30 years have their color expressed in kelvins (2700K, 3500K, 4100K, 5000K, 6000K). Explaining the color of light is another lengthy and difficult discussion. The catalog number of a fluorescent tube does indicate the color of light the tube produces. again, if there are questions, ask a lighting professional.