UL 5085-3:2022 PDF Download

UL 5085-3:2022 is a standard. It is a continuation and expansion of the requirements set forth in Part 1 of the standard, which covers general requirements.

The focus of Part 3 is on Class 2 transformers, which are intended for use with Class 2 circuits. These transformers are designed to be connected to sinusoidal supply sources and are compliant with the National Electrical Code (NEC) in the United States or the Canadian Electrical Code (CEC) in Canada.

Additionally, Part 3 also includes the requirements for Class 3 transformers, which are used with Class 3 circuits in the United States. However, it should be noted that this inclusion only applies to transformers used in the United States, unless otherwise specified in the standard.

The standard explicitly states that it does not cover power supplies (transformers with rectifiers), toy transformers, cord and plug connected transformers other than Class 3, direct plug-in transformers, transformers for audio, radio, or television appliances, or other special types of transformers covered by separate requirements. Transformers with a primary rating higher than 600 V and transformers with overvoltage taps rated above 660 V are also not covered.

Part 3 is meant to be used in conjunction with Part 1, and the numbering of clauses in Part 3 corresponds to those in Part 1. The requirements in Part 1 still apply unless modified by Part 3. The standard also acknowledges that Class 2 transformers containing current-limiting impedance or resonance regulating circuit are covered by its requirements.