NEMA LSD 40
Failure Modes for Self Ballasted Compact Fluorescent Lamps–A NEMA Update
|Publication Date:||1 January 2014|
Introduction and Background
A number of years ago, third party safety agencies such as UL, CSA, and ESA1 reported complaints from consumers regarding the failure modes of self-ballasted compact fluorescent lamps (SBCFL). Media coverage at the time portrayed such complaints as indicative of an issue that could blunt continued acceptance of CFL products by residential users. While the vast majority of CFL products pose no such concerns, it is important to respond to potential consumer concerns, provide additional information, and communicate the actions that have been taken to minimize objectionable failure modes that resulted in these complaints.
Self-ballasted compact fluorescent lamps consist of three primary elements:
A self-contained power supply (commonly called a ballast by the lighting industry) that typically is contained in a plastic housing;
a compact fluorescent tube (spiral or other shape, sometimes covered) that is attached to the top of the plastic power supply housing; and,
a screw base or pin base (as in the case of GU-24 lamps) that allows the SBCFL to be used in many common residential fixtures.
The ballast contains the necessary electronic circuitry to properly start and operate the fluorescent tube as well as to control its power consumption or light output (i.e. dimmable or 3-way CFLs). The fluorescent tube converts electrical energy into visible light without much of the heat produced by an incandescent lamp.
SBCFL products have been adopted by consumers since they only require one fourth to one third of the operating power consumed by a standard incandescent lamp, last six to ten times as long under typical conditions, and significantly reduce greenhouse gas emissions produced by utility power plants.2 The National Electrical Manufacturers Association (NEMA) estimates that in 2012 more than 250 million SBCFL products were sold in the US-many of them to residential consumers. Global regulatory minimum efficacy requirements for medium screw-based lamps are reducing the usage of typical 40-150 watt standard incandescent lamps and will further accelerate the use of SBCFL products in the home.
Residential consumers have generally accepted that SBCFL products look different, and have more application restrictions when compared to the traditional incandescent lamp which has been in use for over 100 years. Although SBCFL manufacturers have continued to reduce these differences to the degree possible, some will persist due to the very different technology presented by a SBCFL in comparison to the 'hot wire in a bottle' technology that is associated with a standard incandescent lamp. Examples of such differences include a noticeable 'warm up' time for SBCFL products that is not present with incandescent lamps and the inability to dim a SBCFL unless it is specifically designed for dimming. Other differences exist as well, but overall, these differences have been accepted as the consumer becomes more familiar with SBCFL operating characteristics since the intrinsic benefits of replacing an incandescent lamp with a SBCFL are so significant for the home owner, the utility, the national and local energy supply, and the environment. It is well to remember that in the early days of incandescent lighting, consumers also had to become accustomed to the different characteristics presented by a new source of illumination as contrasted to earlier light sources such as candles, oil lamps, and gas mantels.
1 UL and CSA are certification agencies that evaluate products and authorize manufacturers to affix the appropriate mark to designate a product meets the applicable requirements. ESA is a Canadian safety authority that educates and represents consumers with respect to product safety matters. ESA is responsible for public electrical safety in the province of Ontario. 2 www.energystar.gov/i