Learn about the update of the UL 1449 Surge Protective Devices (SPDs) standard, adding test requirements for products in humid environments, mainly using constant temperature and humidity tests. Learn what a surge protector is, and what a wet environment is.
Surge protectors (Surge Protective Devices, SPDs) have always been regarded as the most important protection for electronic equipment. They can prevent accumulated power and power fluctuations, so that the protected equipment will not be damaged by sudden power shocks. A surge protector can be a complete device designed independently, or it can be designed as a component and installed in the electrical equipment of the power system.
As mentioned above, surge protectors are used in different ways, but they are always extremely critical when it comes to safety functions. The UL 1449 standard is a standard requirement that today’s practitioners are familiar with when applying for market access.
With the increasing complexity of electronic equipment and its application in more and more industries, such as LED street lights, railways, 5G, photovoltaics and automotive electronics, the use and development of surge protectors are increasing rapidly, and industry standards are of course also Need to keep pace with the times and keep updated.
Definition of Humid Environment
Whether it is NFPA 70 of the National Fire Protection Association (NFPA) or the National Electrical Code® (NEC), the “damp location” has been clearly defined as follows:
Locations protected from weather and not subject to saturation with water or other liquids but subject to moderate degrees of moisture.
Specifically, tents, open porches, and basements or refrigerated warehouses, etc., are locations that are “subject to moderate moisture” in the code.
When a surge protector (such as a varistor) is installed in an end product, it is most likely because the end product is installed or used in an environment with variable humidity, and it must be considered that in such a humid environment, the surge protector Whether it can meet the safety standards in the general environment.
Product Performance Evaluation Requirements in Humid Environments
Many standards expressly require that products must pass a series of reliability tests to verify the performance during the product life cycle, such as high temperature and high humidity, thermal shock, vibration and drop test items. For tests involving simulated humid environments, constant temperature and humidity tests will be used as the main evaluation, especially 85°C temperature/85% humidity (commonly known as “double 85 test”) and 40°C temperature/93 % Humidity The combination of these two sets of parameters.
The constant temperature and humidity test aims to accelerate the life of the product through experimental methods. It can well evaluate the anti-aging ability of the product, including considering whether the product has the characteristics of long life and low loss in a special environment.
We have conducted a questionnaire survey on the industry, and the results show that a considerable number of terminal product manufacturers are making requirements for temperature and humidity assessment of surge protectors and components used internally, but the UL 1449 standard at that time did not have a corresponding Therefore, the manufacturer must conduct additional tests by itself after obtaining the UL 1449 certificate; and if a third-party certification report is required, the feasibility of the aforementioned operation process will be reduced. Moreover, when the terminal product applies for UL certification, it will also encounter the situation that the certification report of the internally used pressure-sensitive components is not included in the wet environment application test, and additional evaluation is required.
We understand the needs of customers and are determined to help customers solve the pain points encountered in actual operation. UL launched the 1449 standard update plan.
Corresponding test requirements added to the standard
The UL 1449 standard has recently added testing requirements for products in damp locations. Manufacturers can choose to add this new test to the test case while applying for UL certification.
As mentioned above, the wet environment application test mainly adopts the constant temperature and humidity test. The following outlines the test procedure to verify the suitability of a Varistor (MOV)/Gas Discharge Tube (GDT) for wet environment applications:
The test samples will first be subjected to an aging test under high temperature and high humidity conditions for 1000 hours, and then the varistor voltage of the varistor or the breakdown voltage of the gas discharge tube will be compared to confirm whether the surge protection components can last for a long time In the humid environment, it still maintains its original protective performance.
Post time: May-09-2023