UL Certification

Würth Elektronik is listed with the high current technology Wirelaid for a number of Underwriters Laboratories (UL) models. Depending on the requirements of the customer, UL identification is possible according to the UL standard UL 94 or UL 796.

Würth Elektronik UL Files:

Testing according to UL 94 (flammability):

The flammability of polymer materials is tested according to Underwriters Laboratories standard UL 94 (among others), whereby a classification of flammability is undertaken.

The best-known classifications are V-2, V-1 and V-0.

UL 94 V 0 (Vertical Burning Test):

During this test, a 20-mm-long controlled flame from a methane gas burner is held for 10 seconds underneath the lower end of a vertically clamped test specimen. After the flame has been extinguished, the procedure is repeated for a further 10 seconds. This is carried out on 5 test specimens. The length of time spent burning and glowing are noted and the sum of these is calculated. Furthermore, the test also records whether any material melts off the test specimen, dripping down and igniting the cotton wool positioned underneath the test specimen.

The UL 94 classification system ranges from V-2 to the best class, V-0. If a test specimen fails to meet the requirements, five more specimens are tested. To achieve the V-0 classification, the cotton wool should not be ignited by glowing or burning drips from the test specimen.

The UL 94 V classifications range from V-2 to the best classification, V-0. If a specimen fails to meet the requirements, 5 additional samples are tested. The V-0 classification requires that the cotton does not ignite through glowing or burning drops.

Testing according to UL 796 (complete):

In addition to combustibility, service life tests at maximum operational temperature are also carried out.

With the certifications, UL has confirmed that our printed circuit boards have passed the tests and meet the requirements for:

  • Maximum operating temperature to 130°C, abbreviated to MOT 130
  • Direct Support Requirement, abbreviated to DSR, for direct operation at mains voltage

Furthermore, labelling with different CTI values is possible (CTI = Comparative Tracking Index, the measure for tracking resistance).

Do you have any questions about UL identification for Wirelaid printed circuit boards?

Then get in touch with our specialist!