What To Do When New Fluorescent Tubes Flicker

A flickering fluorescent is a fascination to fathom. Alliteration aside, you must troubleshoot the system to fix this visual annoyance or change to incandescent lighting. A combination of fluorescent and incandescent lighting will fill in or smooth out the flickering. Fluorescent lamps have more electrical components than the incandescent lamps and more can go wrong. Sometimes fluorescent lamps work in pairs or other combinations. These combinations compound your troubleshooting challenge. Let's start with the basics and the most common causes of flickering.

Try changing the bulb. Even if new, it may be a factory defect. Sometimes an imperfect bulb contact is make on installation. Move bulb back and forth to seat it better in its socket. Flickering bulbs can cause the ballast to heat up and fail prematurely. Discard or return defective bulbs to the store. Black spots at the ends of the bulbs is a sign the bulb is failing. Try a flickering bulb in another fixture. If it stops flickering, the previous fixture may have a bad starter or ballast.

Starters were used on older fixtures, but the newer fixtures do not use them. Starters look like small silver cans about the diameter of a quarter. They twist out by pushing counterclockwise and are usually available at your local hardware store. If you cannot purchase a new starter, test the ballast first.

Ballasts are magnetic or electronic. They should last for decades. The magnetic type costs as much or more than a new fixture. First check with an electrical parts store to find cost and availability. Make sure your starter works before taking this last step.

If the above procedures have not yielded a fixed flicker on the new bulb, consult Section 10: Fluorescent Lighting Troubleshooting (see Resources) for a detailed troubleshooting chart that provides the most probable cause(s) of common problems, along with recommended corrective actions. The table is divided into four categories of fluorescent lighting.