What is a T8 LED Highbay Light Fixture?

First off, let’s get nerdy and learn some lighting lingo. What do “T” and “8” stand for? “T” stands for tubular, and “8” means the diameter of the luminaire bulb. In lighting, if you see a random number, divide it by “8” and you will likely get the diameter of the lamp! For example; a T8 LED bulb is 8/8 = 1” inch, a T12 fluorescent bulb is 12/8 = 1.5” inch. More Examples: PAR38 = Parabolic Aluminized Reflector, 4.75” in diameter. BR30 = Bulged Reflector, 3.75” in diameter. The most common household screw in light bulb is called an A19, and if you do the math, the diameter should be 2.375” inches! To sum it up, basically all lighting parts have a letter or series of letters followed by a number. And they actually mean something!

These fixtures come in 4, 6, or 8 lamp configurations. They are either direct wired from one hot end, or both ends hot called dual ended power. Our fixtures have one end hot, also known as single ended power. Single ended power LED fixtures reduce the amount of wiring, lowering the chances of any type of failures. The wiring; hot & neutral is direct into the “un-shunted” / "non-shunted" tombstones or sockets. The other end of the fixture without wired sockets is often referred to as the “dummy” side. This end of the fixture basically just holds one side of the 4’ foot LED tube in place. These fixtures are typically 4’ foot (48” inches) long, as to distribute light evenly down to the floor reducing hot spots (concentrated light in one area).