Class 2 vs Class II Power Supply: 9 Key Differences

The power supply industry has two concepts which are frequently referred to, and they happen to sound alike: Class 2 and Class II. There is a high chance that they might create misunderstandings. These two classifications serve very different purposes and have distinct implications for safety, application, and design.

What is a Class 2 Power Supply?

A Class 2 power supply is delineated in terms of the maximum power output available for use. This classification is specified by the National Electrical Code (NEC) and is reserved for supplies with defined outputs not exceeding 100VA (Volt-Amperes). The primary goal of Class 2 power supplies is to help mitigate electrical fires by limiting the maximum energy that can be utilized. They are widely used for lighting systems and automation which low-cost electric devices with basic wiring are preferred.

What is a Class II Power Supply?

Double or reinforced insulation that provides additional protection against electric shocks characterizes a Class II power supply. Class II power supplies do not utilize a grounding conductor, which means they do not require a ground wire. Instead, two insulation layers separate the user and the electric current-carrying components in order to guard against electric shocks. Thus, two are sufficient to prevent the user from coming into contact with the live parts of the device.

Class 2 vs Class II Power Supply: 8 Differences

Class 2 vs Class II Power Supply: 9 Key Differences title=

Let’s take a closer look at the 9 key differences between Class 2 and Class II power supplies:

Aspect	Class 2 Power Supply	Class II Power Supply
Standards	UL1310, IEC62368-1 (limits power for safety)	IEC 60529, IEC 60601-1 (double insulation for shock protection)
Safety Protection	Limits power and current to prevent fire and shock risks	Double insulation protects from electric shock without needing ground
Application	Low-power devices, lighting, automation	Consumer electronics, medical devices, appliances
Input Method	Two-wire input for low-voltage, simple wiring	Two-wire input with extra insulation for safety
Logo Identification	No specific logo, but meets required standards	Class II logo (square symbol) shows double insulation and no grounding needed
Use Case	Best for low-power, non-sensitive devices	Best for devices that require shock protection, like medical equipment
Grounding	No grounding needed, easier and cheaper installation	No grounding needed due to double insulation
Shock and Fire Risk	Lower risk of fire due to limited power	Better shock protection with double insulation

Standards and Certifications

Class 2 Power Supply: Class 2 power supplies must adhere to UL1310 and IEC62368-1 standards which places restrictions on the amount of power they can output in an attempt to minimize fire and electrical hazards.

Class II Power Supply: Class II power supplies fulfill safety insulation requirements as per IEC 60529 and also comply with IEC 60601-1 pertaining to medical safety. These standards are based on protective double insulation and electric shock protection.

Safety Protection

Class 2 Power Supply: The Class 2 Power Supply achieves safety by reducing the amount of power and current to limit the risk of fire and shock which inherently makes it safer.

Class II Power Supply: Class II Power Supply secures the user against electric shock through double insulation such that even when there is no ground wire, the user is still fully protected.

Application Scenarios

Class 2 Power Supply: Used in lighting systems, automation and low power devices where the risk of shock or fire is very low.

Class II Power Supply: Used in consumer electronics, medical devices and other home appliances where double insulation is necessary to protect the user.

Input Method

Class 2 Power Supply: For Class 2 low voltage power supply levels the supply has a two wire input. The supply is designed to operate within low power and allow simple wiring configurations.

Class II Power Supply: For class II supplies Purpose two wire input is provided with added emphasis on double insulation for protection against electric shock.

Logo and Appearance Identification

Class II Power Supply: Class II power supples are provided with Class II logo which normally is attached onto the power supply unit or the product papers.

Class II power supples are provided with a square symbol imbedded in another square showing that the device has double insulation and does not require any earthing.

How Do I Know if My Power Supply is Class 2?

A power supply is classified as Class 2 if it has UL1310 or IEC62368-1 certification. Such designs are labeled to signify that they are compliant with the safety requirements for Class 2 devices.

Scope of Application and Compatibility

Class 2 Power Supply: Usually found in low power and non-sensitive applications that only require the safety level of a limited power output.

Class II Power Supply: Most suited in circumstances where protection from electric shock is a necessity like in medical equipment and consumer electronics where safety and insulation are critical.

Grounding Requirements

Class 2 Power Supply: There is no need for grounding which makes the device easier and cheaper to install.

Class II Power Supply: A Class II power supply does not require a ground connection because of double insulation, which makes them safer than Class I power supplies that need to be grounded.

What is the Voltage for Class 2?

Class II power supplies are required not to exceed an output voltage of 60VDC or 42.4 V peak AC for safety compliance.

What is the Current Limit for a Class 2 Power Supply?

Class II power supplies are limited to a provision of 100VA of apparent power in order to help reduce electrical fire and shock hazard.

Risk of Electrical Shock and Fire

Class 2 Power Supply: Their limited power output also means they do not pose a significant fire risk, making them well-suited for low power applications where fire safety is a concern.

Class II Power Supply: Ideal for user-facing gadgets which can be easily mishandled or exposed to moisture, it provides better protection from electric shocks because of its double insulation.

When to Choose Class 2 or Class II Power Supply?

There is a clear dependence on the application as well as the requisite level of protection when making a choice between Class 2 and Class II power supplies. If the focus of your design is economical, while factoring in fire safety, then a Class 2 will be perfect for you. A Class II power supply will be essential if electric shock protection and user safety, especially with medical devices or portable electronic equipment, is the highest priority to ensure the added level of insulation and protection is provided.

Conclusion

Getting the right power supply for your devices is crucial to understanding the distinctions between Class 2 and Class II power supplies. Although they may superficially appear to be the same, their design, safety protections, and applications is where they differ. Whether you want a low-power, budget-friendly power supply or you need a shock-proof design with high safety standards, knowing which certification your power supply has will guide you in making an educated choice.

For applications where fire safety is concerned, choose a Class 2 power supply. For devices needing protection against electric shock, use a Class II power supply.