Direct Wire Tubes
Direct wire tubes are by far the most straightforward, in that they bypass the ballast completely and run directly off line voltage. Not requiring a ballast offers a significant advantage in cost savings throughout the fixtures lifetime, as there is no longer the requirement to replace expensive ballasts that periodically fail or wear out. This really comes into play with big installations such as warehouses and multi-story office buildings, as cost savings per fixture can add up quickly with a large number of fixtures.
Something to keep in mind with direct wire fixtures is that they may require some additional parts to complete retrofitting. Tube lights use “tombstone” sockets to power and hold the bulb, and there are two main types of tombstones used in the lighting industry – Shunted and Non-Shunted. For direct wire fixtures, non-shunted rapid start tombstones are required for proper operation. If the existing fixture is a T12 type, then it should already have the correct tombstone type already installed.
However if it is a T8 type fixture, then the input tombstone sockets will need to be changed over to the Non-Shunted Rapid Start T12 style sockets in order to work properly. This is due to a circular connector in T8 sockets that doesn’t allow them to separate the line or circuits neutral sides properly. Even though this is a pretty straightforward process, it is recommended that a qualified and licensed electrician complete this task since it involves some rewiring. For commercial properties, the use of the correct tombstones is required.
Electronic Ballast Compatible Tubes
Commonly known as “Type-A” or “Plug-n-Play” tubes, electronic ballast compatible tubes are a relatively new addition to the tube lighting marketplace. As suggested by the name, these lights are designed to work with existing tube fixtures equipped with electronic ballasts. Because of this, these lights will not function if installed in fixtures that contain magnetic ballasts or no ballast at all. Because the last generation of fluorescent fixtures exclusively used electronic ballasts, these tubes are becoming one of the most common types sold that work with existing fixtures, and will likely increase in popularity as existing fixtures continue to be retrofitted with LED technology.
These types of bulbs are straightforward to install as they simply require replacing the old fluorescent tube with a new LED tube. Because there are so many different electronic ballasts on the market, LED tube manufacturers have gone through extensive testing to ensure that their electronic ballast compatible tubes will work regardless of the ballast manufacturer. This takes out the guesswork for buyers and makes installation as easy as possible.
While this is great from an ease of use standpoint, it usually results in these tubes having a higher initial cost. On top of this, if the ballast fails then the tube will no longer illuminate which adds to the potential long term costs of this type of LED tube lighting setup. Because of this, ballast compatible tubes usually are only installed on small scale applications where ease of installation is a priority and the relatively low number of ballasts powering the tubes does not present as much of a financial risk.
