Approval vs. Listing
Occasionally an individual will incorrectly ask if an electrical motor is U.L. approved. There is no such thing as U.L. "Approval". The National Fire Protection Association defines "Approval" to be "Acceptable to the authorities having jurisdiction"; and they define "Authorities having jurisdiction" as being those responsible or concerned with the installation (Government agencies, users, insurers, etc...). These authorities in turn will usually accept equipment that has been "Listed" by an acceptable organization such as Underwriters Laboratories (U.L.). This "Listing" means that certain evaluations of concern have been made by the organization. A Listing mark (Label) on the equipment is the manufacturer’s indication that the Listing requirements have been met.
Listing Component Parts and Component Recognition
When U.L. "Lists" electrical equipment, they take into consideration various component parts. The acceptability of these component parts depends on their application in the end product equipment, their inter-relationship with the other components, and the end-product equipment’s performance/safety requirements. U.L. has a program by which a manufacturer of the component parts can obtain what is called "U.L. Component Recognition". This is a program by which U.L. "partially" covers the part with its final acceptability depending on, and evaluated by, its use in the end-product equipment. U.L. recognized component parts do not get a U.L. Listing mark, but their use in the end-product equipment can assist the end-product equipment manufacturer in obtaining his U.L. Listing. However, use of U.L. component recognized parts is not necessary in obtaining U.L. Listing of end-product equipment.
U.L. however has a U.L. recognition mark which is the mirror image of the letters RU. U.L. has given the motor manufacturer the choice of whether or not to use this mark.
Electrical Motors
Electrical motors perform various functions as component parts of end-product electrical equipment. Because of their many usage motors are subjected to varied environmental circumstances. As a result, U.L. evaluates motors as component parts within the scope of end-product equipment listings. U.L. Component Recognition of motors can assist the end-product equipment manufacturer; however, U.L. Component Recognition of a motor is not necessary in his obtaining U.L. Listing. In any case, it is the end-product equipment manufacturer that gets the Listing and his end-product equipment that gets the U.L. Listing mark. The motor manufacturer does not get Listing except in the special case of hazardous location motors where the Listing applies to the motor’s risk of being a source of ignition by itself.
Conclusion for Electrical Motors
The term "U.L. Approval" is not a correct term, and with respect to equipment using electrical motors, the correct terminology, "U.L. Listed" applies to the end-product equipment using the motor as a component part (except as indicated above for hazardous location motors). Obtaining U.L. Listing is the responsibility of the manufacturer of the end-product equipment for which the electrical motor is a component.
If a U.L. Recognized Component motor is to be specified to assist the end-product equipment manufacturer in obtaining Listing, the motor manufacturer must be advised at the time of quotation/order-entry.