BULLETIN: Decorative Lighting Strings

Updated May 29, 2025 with new table data

Decorative lighting strings including holiday, seasonal or Christmas lights can carry potential safety risks when subjected to unforeseen consumer misuse or when they are not manufactured in accordance with UL Solutions' safety requirements. The familiar UL Listing Mark on a product means that UL Solutions engineers have evaluated and tested representative samples of the product for risk of fire, electric shock and other hazards and determined the samples conformance to UL Solutions' requirements. Indoor-use only light strings are marked with UL Solutions green holographic label. Indoor or outdoor-use light strings are marked with UL Solutions red holographic label.

UL Solutions evaluates decorative lighting strings in accordance with the requirements described in the UL / ANSI 588, the Standard for Safety of Seasonal and Holiday Decorative Lighting. The ANSI designation indicates that the American National Standards Institute approves the UL Standard as the American National Standard.

Most retailers will only sell decorative lighting strings that have been evaluated to this Standard.

UL 588 and the Two Strike Program

In order to verify that lighting strings are manufactured in accordance with UL Solutions' requirements, UL Solutions introduced an enhanced factory surveillance program. Under this program, samples are selected from each active manufacturer twice a year for testing.

Various components of the product are subjected to tests at UL Solutions including the wire, plastic material, and lamp holders. If UL Solutions finds a major failure, the product is placed on hold, and the applicant and manufacturer are issued a program nonconformance. This nonconformance is known as a Strike. The manufacturer is not permitted to apply the UL Mark until it can provide a suitable root cause of the failure and put into place the necessary corrective action. The manufacturer will then need to resubmit samples to UL Solutions that were manufactured after the corrective action was put into place and determined to comply with the requirements. The factory is then placed on an increased surveillance program until it is determined that the corrective action has been effectively put into place.

In addition to UL Solutions factory surveillance program, samples of lighting strings may be purchased from the marketplace during the selling season for testing under the UL 588 Market Survey program. If there is a test failure under the program, the applicant and manufacturer are issued a strike. Two strikes occurring within a two-year period result in withdrawal of the applicant and manufacturer and ultimately termination of its use of the UL Listing Mark for decorative lighting strings.

UL Solutions Decorative Light String No Strike List

No Strike List-1: Consists of applicants with manufacturers that have had samples selected during the Market Survey program and have not had a strike under the UL 588 Two Strike Program for a minimum of three consecutive years.

No Strike List-2: Consists of applicants with manufacturers that have not had a strike under the UL 588 Two Strike Program for a minimum of three consecutive years but did not have samples selected during the Market Survey program.

Any questions please contact:
Anthony Tassone
Principal Engineer
Tel: +1.631.546.2943
Anthony.T.Tassone@ul.com

Decorative Lighting Strings - No Strike List

Revised: May 29, 2025

Decorative Lighting Strings - No Strike List - 1

Decorative Lighting Strings - No Strike List - 2