Ul 242 [updated] | 2026 Edition |

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:

By meeting the requirements of UL 242, manufacturers can ensure that their medium-voltage power cables meet rigorous safety standards, reducing the risk of electrical shock, fires, and other hazards. ul 242

To earn a UL 242 certification, venting equipment must undergo rigorous testing to ensure it can withstand the harsh environments of petroleum storage. The standard isn’t just about surviving a splash

The result was a slow, invisible disaster. Moisture would creep into the thermostat housing. Inside, it would corrode contacts, bridge terminals, and eventually cause one of two failures: To earn a UL 242 certification, venting equipment

Standardized vents, particularly conservation vents, help minimize the release of harmful Volatile Organic Compounds (VOCs) into the atmosphere.

These are often "weighted" to remain closed until a specific pressure or vacuum threshold is reached, helping to reduce evaporative losses of volatile fuels. 2. Key Testing Requirements

UL 242 is specifically a standard for "Standard for Medium-Voltage Power Cables (5000 Volts and Above)". This standard covers the requirements for the design, construction, testing, and marking of medium-voltage power cables with extruded insulation rated for 5000 volts and above.