1 Scope

1.1 As noted in Low Voltage Transformers – Part 1: General Requirements, UL 5085-1, or CSA C22.2 No. 66.1, Low Voltage Transformers – Part 1: General Requirements, the requirements in Part 3 cover Class 2 transformers for use with Class 2 circuits in accordance with the National Electrical Code, ANSI/NFPA 70, or the Canadian Electrical Code, Part I, CSA C22.1. They are intended for connection to essentially sinusoidal supply sources.

Advisory Note

1.3 In addition to the items specified in Clause 1.3 of Part 1, the requirements of Part 3 do not cover:

1. a) Power supplies (a transformer provided with a rectifier is considered a power supply);

2. b) Toy transformers;

3. c) Cord and plug connected transformers other than Class 3;

4. d) Direct plug-in transformers;

5. e) Transformers intended for use in audio, radio, or television type appliances; or

6. f)  Other special types of transformers covered in requirements for other electrical devices or appliances.

Advisory Note:

1.7 This part is intended to be used in conjunction with Part 1. The numbering of the clauses in Part 3 corresponds to the numbered clauses in Part 1. The requirements in Part 1 apply unless modified by Part 3.

1.8 A Class 2 transformer that includes a separate current-limiting impedance such as a resistor or a positive temperature coefficient device (PTC) is covered by these requirements.

1.9 A Class 2 transformer that includes a resonance regulating circuit is covered by these requirements.