Direct vs. Bypass

January 12, 2020 by Chaim Gluck

With all the talk about the benefits of LED, many people have come to us with questions about how they can switch over their existing bulbs to LED.

With most basic lighting applications, changing out the bulb for an LED equivalent option is as simple as unscrewing the old and screwing in the new. Where things start to get more complicated is when there is a ballast involved.

How do Ballasts Work?

When it comes to fluorescent tubes or CFL plug in bulbs which have a ballast regulating the electrical flow, there are two main options for LED, Plug n Play/Direct or Bypass.

Plug n Play/Direct is exactly what the name suggests. An LED tube that works with the existing ballast already in place in the fixture. All you have to do is swap out the existing fluorescent tube for the LED model and you should be good to go. No re-wiring or ballast change needed.

Bypass/Direct is when the LED tube is made to work directly with the line voltage. In this case the existing ballast is removed, and the line voltage is wired directly to the sockets.

There is also a third option known as Hybrid or Dual technology which allows the bulb to work with either the ballast or with the line voltage directly.

Pro's and Con's

  • Plug n Play
    • Pros
      • Simpler for installation purposes
      • Safer installation- less time on a ladder = safer
    • Cons
      • Still uses ballast which needs to be replaced
      • Not compatible with all ballasts. Each manufacturer has their own list.
  • Direct Wire
    • Pros
      • No longer uses a ballast- no ballast maintenance
      • No loss of wattage/power because of ballast- Energy is lost as it goes through the ballast. This is called ballast factor.
    • Cons
      • Fixture needs to be re-wired which leads to greater possibility of safety risk. Labor costs are increased
      • Socket compatibility- you may need to change your sockets from the most common shunted sockets to non-shunted sockets. Non-shunted sockets are required if you're using single-ended tubes. This will require a small amount of additional material cost and more labor to replace them all.

Ultimately you are making the right choice with either technology, and saving yourself energy in the long run.