Thursday, May 5, 2016

LED Tubes - Type A, Type B and Type C

You may have heard the some people refer to LED Tubes as Type "A", Type "B" or Type "C" tubes. What does that mean? Here is a simple guide to assist you

Type "A" LED Tubes (Ballast Compatible - Plug and Play)

These are tubes that work with the existing ballast of the fluorescent fixture. Let us state one item very clearly. It works with most ballasts (but not all ballasts). There are still some old ballasts on the market and not all of them have been tested with the LED drivers inside these tubes. So it is always a good idea to test a companies tubes in your fixtures before you do a major purchase. Also, it is not uncommon for a company to have many different ballast types in their fixtures. Sometimes the tubes will work with 98% of their existing fixtures, but not all. What can you do? There are 2 options. First option is to replace the ballast to one that will work. The second option is to consider a hybrid tube (see below)

Please note. The fluorescent ballast is still a point of failure. At some time in the future, the ballast will fail. So even though you may think you are going to save on installation using these tubes, they will eventually force you to replace the ballast.

Ballasts consume energy. You will get the benefit of using less power with the LED tube, but the ballast still consumes power (ballast draw), so your savings won't be as great as if you switch over to a tube that does not use a ballast. However, the power draw should be very little.

Type "B" LED Tubes (Internal Driver)

All LED bulbs use drivers that power the LEDs. They perform the function of converting AC power from the utility company into DC power. LED Lights run on DC power. Some LED Tube manufacturers incorporate the drivers inside the tubes. These tubes are call Type "B" LED Tubes.

A Type B LED Tube comes in two varieties, Single Ended Power and Double Ended Power. Single Ended Power (SEP) tubes take power at only one end of the tube. It uses an unshunted tombstone to power it. The other end is just a dummy end. On the power end, there are two pins. One pin takes line power, the other pin take neutral.

Double Ended Powered (DEP) means you send power to each end. This is similar to how fluorescent tubes run. In the case of LED Tubes, you send line to one end and neutral to the other end. Typically it does not matter what end is wired to line or neutral, but check with the manufacturer's instructions to make sure.

Most important in this installation, the ballast is removed or bypassed. AC Power is sent directly to the tube. So although installation is more involved, you have permanently removed the ballast from the fixture.

Type "C" LED Tubes (External Driver)

An external driver tube is the least common tube available on the market today, but it is the one that most closely resembles a fluorescent tube installation. A fluorescent tube consists of tubes and an external ballast, and a Type "C" tube consists of a LED Tube and an external LED Driver.

In this installation, the fluorescent ballast is removed and the driver is installed in the ballast location. All the wires are connected the same, with DC + going to one end and DC - going to the other end.

There are many advantages to this design. First, it is very safe. Low voltage DC power is sent down to the lamp holders. Second, if the driver ever fails, you can replace the driver. However, this also tends to be the most expensive of the 3 solutions. External LED drivers are not cheap.

Hybrid LED Tubes

A Hybrid LED tube is a combination of Type "A" and Type "B" tubes. This is a tube that can (may) work with the existing fluorescent ballast, or can operate without the ballast. This is an excellent choice for those installations that want to use the fast installation method using the ballasts but have a backup plan if the ballast is not compatible. Some of the more clever designs allow the tube to be both SEP or DEP. Our Hybrid tube is one of those clever designs.


  1. LED Tubes manufacturer

    Please Click Above Link here & Get information and latest ideas about Best, brother lux

  2. Thanks a lot for sharing. It was jus what i was looking for

  3. I am thankful to this blog for assisting me. I added some specified clues which are really important for me to use them in my writing skill. Really helpful stuff made by this blog.
    โคม ไฟ led