Do the UL Standards Make Sense for LED Christmas Lights
(*Since the writing of this article UL has updated their standards for LED Christmas lights. Read about the new UL standards.)
Underwriter's Laboratory (UL) is a non-governmental for-profit product safety certification organization. UL has become the industry standard for safety certification of electronic devices in the U.S. UL certification is not a legal requirement but most reputable companies who manufacture or sell electronic devices seek the certification of UL.
In order to obtain UL approval for a product the product must meet the standards created by UL for that specific type or class of electronic device. UL's standards also proscribe the conditions under which the certified product or prospective certified product may be used. UL has a standard for decorative lighting strings or common Christmas lights. The use standards UL proscribes for Christmas lights are the same regardless of whether the light string utilizes a incandescent or LED light source. There are two use standards that are somewhat outdated when it comes to Christmas lights using LEDs. The current UL use standards state that Christmas lights (whether LED or incandescent):
- Are only certified for seasonal use which is defined as less than 90 days; and
- Can only be connected up to 3 sets end-to-end.
Because the technology, energy consumption, and nearly every other aspect of LED Christmas lights is so different from incandescent lighting technology it is a bit of a mystery why the UL standard and use requirements are the same for both types of decorative string lights.
A typical incandescent mini-light consumes about .50 watts of electricity. A comparable LED light consumes about .05 watts or less. This means that the power draw is at least 80% less in an LED than it is in an incandescent light set yet the use restrictions are the same.
Most high-quality LED holiday or decorative lighting sets will last for more than 50,000 hours and reputable manufacturers will warrant them for 3 years for more even if used outdoors continuously for that period. So why does UL state that the light sets can only be used for "seaonal" use not to exceed 90 days?
The answer is simple, and it is the same for the issue related to end-to-end connection: UL's standards are out of date and do not take into consideration the significant differences between LED Christmas lights and incandescent Christmas lights.
We are currently conducting some testing using LED Christmas lights which is being overseen by a licensed electrician. We will report on the outcome of this testing and discuss how our results vary from the current UL standards.