Field modification and labeling

Field modification

UL Listed product modified in the field

An authorized use of the UL Mark is the manufacturer's declaration that the product was originally manufactured in accordance with the applicable requirements when it was shipped from the factory. When a UL-Listed product is modified after it leaves the factory, UL is unable to determine if the product continues to comply with the safety requirements used to certify the product without investigating the modified product. UL can neither indicate that such modifications nullify the UL Mark, nor that the product continues to meet UL's safety requirements, unless the field modifications have been specifically investigated by UL. It is the responsibility of the authority having jurisdiction (AHJ) to determine the acceptability of the modification, or if the modifications are significant enough to require one of UL's Field Engineering Services members to evaluate the modified product. UL can assist the AHJ in making this determination.

If a party wishes UL to determine if the modifications made to a UL Listed product comply with UL requirements, the appropriate Field Engineering Service can be initiated to investigate the modifications. This investigation will only be conducted after UL consults with the AHJ to determine that UL's investigation addresses all areas of concern and meets all of the AHJ's needs. Please contact Regulatory Services to inquire about a Field Investigation.

Field labeling

Application of a UL Mark in the field

The application of a UL Mark in the field is only permitted when an inspection is conducted in accordance with one of UL's Field Engineering Services in the presence of a UL representative.