Class 2 power transformers are fundamental components across diverse sectors like industrial controls, consumer electronics, landscape lighting, and the food and beverage industry. Characterized by their safety-oriented design, these transformers operate with low secondary voltages to minimize electrical shock risks and low power to decrease fire hazards. This careful design not only meets strict industry standards but also improves safety and efficiency in many different applications.

On this page, you’ll learn more about the purpose, design, and benefits of Class 2 transformers, so you can select the right device for your application.

What Is a Class-2 Power Transformer?

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A Class 2 power transformer is a transformer that can safely handle a maximum secondary potential of 30 volts rms (root mean squared) under any loading condition. The transformer acts as a safe, reliable conduit between the power source and the connected devices.

Purpose of Class-2 Power Transformers

Class 2 transformers manage voltage levels for Class 2 circuits. These circuits are found in many essential applications, from commercial ovens to air-conditioning thermostats. The primary purpose of Class 2 transformers is to protect the circuit from overloading thermal fuses or prevent failure. As a result, Class 2 transformers improve overall safety against electrical shocks and minimize electrical fire risks.

Class 2 transformers are used in Class 2 circuits that must comply with key standards such as ANSI/NFPA 70, the Canadian Electrical Code Part 1, CSA C22.1, and UL 5085-1 & 3. The end product or application determines which category of transformer is appropriate. These standards guarantee that the transformers operate safely within the specific requirements of the electrical systems they are integrated into.

Design of Class-2 Power Transformers

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Class 2 power transformers can be inherently limited—self-regulating through impedance or positive temperature coefficient (PTC) devices—or non-inherently limited, relying on external overcurrent and overtemperature protection mechanisms. Regardless of whether the transformer is inherently limited vs. non-inherently limited, both types of designs are sufficient to ensure device safety.

UL (Underwriters Laboratories) requires Class 2 transformers to meet numerous safety standards, including those related to controlling output current, output power, and output voltage. The main standard UL uses in the certification of Class 2 transformers is UL 5085-1 and 3. Some downstream devices could require a Class 2 power source, so system designers need to provide the appropriate Class 2 transformer for proper implementation.

The routing of Class 2 circuits must be done separately from other circuits, both in field raceways and control enclosures. Class 2 designs must also consider the limited amount of available power for each circuit and, therefore, the limited number of downstream devices that can be powered.

Benefits of Class-2 Power Transformers

By integrating Class 2 transformers, product designers and suppliers can benefit in the following ways:

  • Safer Designs: Class 2 transformers are built to minimize the risks of electrical shocks and fires, ensuring a safer operating environment. Downstream devices would require no further protection from these hazards.
  • Simplified Circuitries: Class 2 transformers can be made smaller and the circuitry less complex, making installation and troubleshooting easier.
  • Cost-Effectiveness: The simplified design reduces procurement, installation, and maintenance costs associated with using Class 2 transformers.
  • Compliance Ease: Generally, manufacturers apply for NEC Class 2 certification by submitting their devices to UL. Once the device is certified, designers can use it more easily than if they were to use other types of components. For example, in UL 508A-listed control panels, all Class 2 circuits and any connected components do not need to be evaluated for UL compliance, streamlining the panel design process.

Learn More About Class-2 Transformers From Triad Magnetics

Class 2 power transformers are crucial in environments like food service and food processing facilities, which need reliable equipment to facilitate safe, efficient production. Investing in Class 2 power transformers can prevent equipment cables and other components from overheating or shorting out. Partner with Triad Magnetics to improve the safety, reliability, and efficiency of your food processing or other industrial equipment.

Here are our standard Class 2 transformer product families:

Our experts are ready to provide a standard or custom Class 2 power transformer solution to fulfill your specific needs. Request a quote or contact us today to get started on your solution.