From 24V to 69kV, transformers are a critical part of many electrical systems that are used to increase or decrease the voltage in electric power applications. UL evaluates transformers to a broad range of U.S. and international standards. In addition to safety testing, we can also evaluate transformers for efficiency and K-factor ratings.

Like other industrial equipment, many transformers can be evaluated as open type or enclosed. Open-type equipment is ultimately installed in an enclosure before being put into service; whereas, enclosed transformers can be rated for indoor use or any NEMA or IP rating requested. In addition, these can be certified for use in classified areas (e.g., hazardous locations).

Manufacturers needing a high temperature insulation system class (above Class A) are encouraged to use an adopted insulation system to avoid long-term aging testing. You may use UL’s IQ database to search for systems by using a variety of parameters.

As alternative energy needs grow, the demand for medium voltage transformers also grows. UL utilizes IEEE standards for these types of transformers, such as the IEEE C57.12 and C57.13 series of standards.

In addition, UL has several categories for current transformers, the newest being UL 2808, the Outline of Investigation for Energy Monitoring Current Transformers. These are listed, and suitable for field installation into panelboards (load centers).

Having a product certified to IEC standards and receiving the UL Mark can enable your product’s market potential to expand globally. Additionally, access to global markets can be made easier by having testing and certification for multiple requirements done at the same time. UL uses IEC 61558, IEC 60076 and IEC 61869.

The UL Certification Mark is an ISO Guide 17065/17067 type 5 scheme that gives the manufacturer an opportunity to demonstrate continued compliance with the Type Examination requirements of the IEC standard group, with the benefit of real-time online listing in the UL Online Certifications Directory. This offers the highest level of integrity and compliance in the market for transformers.