InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.
To fix a flickering fluorescent light fixture we will be successful more quickly and at a lower cost if we take a few minutes to figure out what's wrong:
Is it the bulb, a connection, a loose wire, a bad starter, a bad ballast or transformer, or something else?
To sort out the causes and cures for flickering fluorescent lights we start by listing the causes of this annoying problem. After reviewing the causes of flickering lights we continue with the most-likely repair: diagnosing a bad bulb or lamp.
This article series explains how to diagnose the causes of flickering or dimming fluorescent light fixtures in buildings.
Watch out: flickering or dimming lights might indicate a dangerous condition risking a building fire or an electrical shock. If the simple bulb or starter repairs we describe here don't cure the flickering, switch off the bad-acting light fixture, leave it off, circuit and ask for help from a licensed electrician.
We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.
Causes of Flickering Fluorescent Light Fixture
Properly-functioning fluorescent lights should not produce a flickering that is noticeable. Standards for ballasts typically state:
Ballasts shall operate lamps with no visible flicker (<3% flicker index).
Traditional fluorescent lamps using a magnetic (old style) ballast may produce a high-frequency flickering that is sometimes barely noticeable. Fluorescents using a newer electronic ballast should will never show visible flickering unless there is another problem present.
More noticeable fluorescent lamp flickering occurs at the end of the fluorescent lamp's life and is a sign that the lamp (bulb) is ready for replacement.
However there are other sources of abnormal flickering fluorescent light fixtures that mean repairs are needed.
Common causes of flickering fluorescent light fixtures
Bad electrical contact - between the pins at the end of the fluorescent tube and the metal contacts or clips inside of the tube socket at each end.
A fluorescent bulb that has not been properly seated into its contacts at both ends is, in my experience, one of the most-frequent causes of flickering or poorly-operating lamps.
Before even thinking about installing a new bulb, try rotating the tube back and forth 45 degrees in its socket to see if improved contact stops the flickering.
Watch out: take care not to use too much force nor to break the bulb as doing so exposes you to dangerous glass fragments and mercury dust and vapor.
A bad fluorescent light bulb - notice dark or black burn marks near the ends of the tube - an indicator of age and possibly that the tube is at end of life. try replacing the bulb with a known-good one;
Bad bulb connector: loose or damaged pins in the ends of the fluorescent light bulb (lamp) itself (uncommon) - you'll discover this by inspecting the pins on the end of the lamp: if a pin is bent, loose, or broken, replace the bulb.
Don't try to straighten a severely-bent pin: the risk is that you'll break the bulb or render its contacts and electrodes unsafe.
Bad wiring or switch: a loose or bad electrical wire connection or splice in the light switch or in the circuit supplying power to the light fixture.
An electrician will check wiring connections and splices and perhaps trace the circuit for a loose connector upstream.
Unsafe electrical circuit breaker or unsafe electrical wire: some brands of circuit breaker may cause flickering lights or may fail to turn off in response to an over-current or short circuit, and may even fail to turn off internally when the toggle is switched to the OFF position.
Aluminum branch circuit wiring, found in some older homes wired in North America in the 1970's can overheat enough to start a fire without ever tripping a circuit breaker. Flickering lights can be a symptom of this problem developing IF your home uses aluminum wire.
Voltage variations - or "voltage flickering" traced to the electrical power source.
Research on Flickering Fluorescent Lighting
Sun, J., D. Czarkowski, and Z. Zabar. "Voltage flicker mitigation using PWM-based distribution STATCOM." In Power Engineering Society Summer Meeting, 2002 IEEE, vol. 1, pp. 616-621. IEEE, 2002.
Veitch, Jennifer A., and Shelley L. McColl. "Modulation of fluorescent light: Flicker rate and light source effects on visual performance and visual comfort." Lighting Research and technology 27, no. 4 (1995): 243-256.
Wilkins, A. J., I. Nimmo-Smith, A. I. Slater, and L. Bedocs. "Fluorescent lighting, headaches and eyestrain." Lighting Research and Technology 21, no. 1 (1989): 11-18.
Winterbottom, Mark, and Arnold Wilkins. "Lighting and discomfort in the classroom." Journal of Environmental Psychology 29, no. 1 (2009): 63-75.
Zweers, T., L. Preller, B. Brunekreef, and J. S. M. Boleij. "Health and indoor climate complaints of 7043 office workers in 61 buildings in the Netherlands." Indoor Air 2, no. 3 (1992): 127-136.
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: firstname.lastname@example.org. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides extensive home inspection education and report writing material.
The Illustrated Home illustrates construction details and building components, a reference for owners & inspectors. Special Offer: For a 5% discount on any number of copies of the Illustrated Home purchased as a single order Enter INSPECTAILL in the order payment page "Promo/Redemption" space.
TECHNICAL REFERENCE GUIDE to manufacturer's model and serial number information for heating and cooling equipment, useful for determining the age of heating boilers, furnaces, water heaters is provided by Carson Dunlop, Associates, Toronto - Carson Dunlop Weldon & Associates Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page "Promo/Redemption" space.
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume.
Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on these courses: Enter INSPECTAHITP in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
The Horizon Software System manages business operations,scheduling, & inspection report writing using Carson Dunlop's knowledge base & color images. The Horizon system runs on always-available cloud-based software for office computers, laptops, tablets, iPad, Android, & other smartphones