The UL Listing process

The following is intended to provide information for the majority of listing investigations. New technologies or applications may, however, require special investigation techniques not covered below.

UL 1703, the Standard for Safety of Flat-Plate Photovoltaic Modules and Panels details UL's current product requirements for this category of equipment. For products that employ power connectors, those connectors are normally investigated using UL 498, the Standard for Safety of Attachment Plugs and Receptacles and/or UL 1977, the Standard for Safety of Component Connectors Used for Data, Signal and Power Equipment Applications. Note that electrical connectors will need to be certified for outdoor use in wet locations with exposure to sunlight i.e., UV exposure resistant. If a customer should choose to create a Listed power connector for use with PV modules and panels, please also note that these devices must be designed robustly enough to withstand use as a DC circuit interrupt device under overload conditions as outlined in UL 498 and UL 1977.

For manufacturers new to UL, it is important to understand that the construction of the product, the safety performance materials and the manufacturing process are all assessed in determining the compliance of the module or panel to the requirements of UL 1703. The product's output wiring system will also be investigated for conformance with the conventions of the U.S. national electrical code (NEC) published by the National Fire Protection Association.

Submitting a photovoltaic product for evaluation may be accomplished along two different paths depending on where in the product developmental process and the confidence level the manufacturer has in meeting the Listing requirements. A fairly well developed product can be submitted for the entire listing investigation, or it may be submitted (especially a product that is currently being developed) for a preliminary investigation to review the construction, design and materials of the product.

In the preliminary investigation, UL will review the product's major construction features and provide feedback on areas of concern prior to engaging in the more detailed construction and performance evaluation associated with a listing investigation. This allows a client the opportunity to modify construction features prior to the full listing investigation. Upon request, UL can also conduct any part(s) of the test program outlined in UL 1703 during the preliminary investigation. For those not familiar with UL or the submittal process or not fully confident of product performance during some of the testing, this approach is a less expensive and a more time efficient way to confirm initial construction conformity and will minimize delays in the final testing and Listing process.

Prior to sending out the UL service agreement forms for a listing or preliminary investigation, we will ask for a letter outlining the scope of the evaluation desired as well as a detailed description of the construction and performance features of the product. Please see sample and information requirements for additional information.

UL will request specific information on the construction of the substrate and superstrate material. If polymeric materials are used for these surfaces or in any other enclosure around live electrical parts (such as custom junction boxes or covers), please identify the material's UL Recognition including the manufacturer, its trade name, designation and how the materials are employed.

Please also include any schematic diagrams, list of components used and type of wiring used.

In order to prepare the service agreement forms, UL will request the name and address of the company who is applying for Listing (applicant), the company who will legally be responsible for the Listing (listee), and the company who will be manufacturing the product (manufacturer) if they are different from each other.

Once we receive the above information, we will be able to determine the cost limit and prepare the appropriate application forms.