Technical Articles

What is the difference between UL 489 and UL 98?

When it comes to circuit protection, two common standards that are often referred to are UL 489 and UL 98. While both of these standards pertain to the safety and performance of electrical devices, there are some important differences between them.

UL 489: Ensuring Circuit Breaker Performance

UL 489 is a standard established by Underwriters Laboratories (UL) for molded-case circuit breakers. This standard specifically focuses on the breaking capacity, overcurrent protection, and other performance aspects of circuit breakers. It ensures the reliability and safe operation of circuit breakers in various applications. In order to comply with UL 489, circuit breakers have to undergo rigorous testing, including overload and short-circuit tests, to demonstrate their ability to interrupt faults and protect electrical systems from damage.

UL 98: Safeguarding Switches and Disconnects

In contrast to UL 489, UL 98 applies to switches and disconnects. It sets requirements for enclosures, contact arrangements, and ratings of switches used in electrical systems. UL 98 aims to ensure the safe disconnection of power sources from equipment during maintenance, repairs, or emergencies. These switches and disconnects need to meet specific performance criteria to prevent electric shock hazards and ensure reliable disconnection of electrical circuits.

Key Differences between UL 489 and UL 98

While both UL 489 and UL 98 are important standards for electrical components, here are some key differences:

Focus: UL 489 is primarily concerned with circuit breaker performance and protection, while UL 98 focuses on switches and disconnects.

Testing: Circuit breakers have to undergo rigorous overload and short-circuit tests to meet UL 489 requirements. On the other hand, switches and disconnects are subjected to different performance tests specified in UL 98.

Application: Circuit breakers are commonly used in electrical distribution systems, including residential, commercial, and industrial applications. Switches and disconnects, on the other hand, are typically utilized for manual control and disconnection of power sources.


UL 489 and UL 98 are both important standards that ensure the safety and performance of electrical devices. While UL 489 focuses on circuit breakers, UL 98 sets requirements for switches and disconnects. Understanding these differences is crucial for selecting the appropriate components for specific applications, as both play vital roles in protecting electrical systems and ensuring the overall safety of personnel.



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