Posted by Doug Root on 3rd Aug 2018

Keystone LED T8 Lamps - DirectDrive, SmartDrive, ComboDrive

One of the biggest changes and improvements we have seen in the LED lighting industry is with the  Keystone LED T8 lamp. Just 3 years ago these lamps would cost a commercial buyer about $50 each. Now, they range from $5 to $15 in price and offer great benefits.

We are particularly impressed with  Keystone Lighting Technologies because they have a great roadmap for their LED lamps. Keystone began manufacturing ballasts in 1945 but changed their product offerings to LED lamps in recent years. Now, Keystone LED T8 lamps are some of the best LEDs available.

Keystone has 3 very different options when it comes to LED T8 lamps:  DirectDriveSmartDriveComboDrive. Each has its own features that make it a contender for the being the best Keystone LED.


The DirectDrive LED T8 lamp is also known as the "ballast bypass" lamp. DirectDrive LED tubes eliminate the need for an external driver or ballast. For new construction installations, simply connect the 120-277V line voltage directly to the sockets. For retrofit installations, bypass the existing ballast by cutting the wires and connecting the 120-277V line voltage directly to the sockets.

DirectDrive Keystone LED T8 lamps have a single end live feed. In the past year manufacturers have begun to also offer double ended LED T8 ballast bypass lamps. For this conversation we are only looking at the single ended LED T8 ballast bypass lamps. Of note, it is extremely important to fully understand which lamp you are choosing and the proper way to rewire and relalbe the altered fixture. Always have a certified electrician do your installation. Each lamp comes with a label for marking changes made to existing fixtures that are being retrofitted from fluorescent to LED DirectDrive.

Note: DirectDrive LED T8 lamps will only operate on non-shunted sockets. Typically, these sockets are in T8 fluorescent instant start fixtures. Verify non-shunted sockets are installed before using a DirectDrive LED. Below are a few pictures of the various socket configurations you may find.

Non Shunted and Shunted SocketsNon ShuntedSockets


The SmartDrive Keystone LED T8 lamp is known as the "ballast dependent" lamp. These are the easiest to install, which may make them the best Keystone LED. Switching from fluorescent lamps to LED SmartDrive lamps is as easy as changing a light bulb. Simply remove the existing fluorescent lamps and replace with Keystone SmartDrive LED tubes.

No special instructions, no tools, no rewiring. The LED tubes run off the existing T8 instant or program start electronic ballast. These lamps are DLC qualified and offered with shatterproof coating if needed. They are UL classified and come with a 5-year limited warranty. Visit  Keystone Ballasts to review a ballast compatibility list.


The ComboDrive Keystone LED T8 lamp is the best of both worlds. These lamps can be directly wired to main power or operate on a compatible instant start or programmed start electronic ballast. When using these lamps and direct wiring them to main power, you must use non-shunted sockets. The Keystone ComboDrive lamps are also single end powered lamps. These lamps will operate on most instant start or programmed start electronic T8 ballast. For compatibility, please see Keystone Ballasts.

Atlanta Light Bulbs offers the best solutions in both commercial and residential lighting. Browse our selection of LED lighting and more today!