Ul 242 ((top)) Jun 2026

In the world of safety standards, some numbers become legendary: UL 217 for smoke alarms, UL 94 for flammability. But tucked away in the appendices of electrical codes is a quieter, yet equally vital, number: .

To understand UL 242, you have to step into a damp, steamy, and often forgotten battlefield of home safety: the bathroom. Specifically, you need to look at the small, utilitarian box on the wall—the electric water heater thermostat. ul 242

The standard isn’t just about surviving a splash. It’s about surviving the entire life of a water heater in a wet environment. To earn UL 242 certification, a thermostat must pass a gauntlet of tortures: In the world of safety standards, some numbers