UL 20 is the standard used to evaluate which type of device for electrical safety?

• A. Snap switches
• B. Receptacles
• C. Circuit breakers
• D. Wires

Answer: (A)

UL 20 is the standard that governs the safety and performance of snap switches. Snap switches are the common manual switches used to turn circuits on and off, like light switches. The standard sets out how these switches must be built and tested to ensure they’re safe to operate over their expected life. It covers aspects such as mechanical durability, electrical contact resistance, insulation, and dielectric strength, plus the test methods used to verify these qualities. Because of that, UL 20 is the applicable safety standard for snap switches.

Receptacles, circuit breakers, and wires are evaluated under different standards tailored to their specific functions—receptacles under standards related to outlets, circuit breakers under standards for protective devices, and wires under standards for conductors.