Why Didn't Your Product Pass the UL 4200A Test?

After publishing our article yesterday, we received a lot of feedback. Based on this feedback, Huayu Testing has collected and summarized some experiences and examples of passing the UL 4200A test.

According to UL 4200a-2023 Clause 5.6, if the battery cover is secured with screws, the screws must remain attached to the battery cover. In the product shown, the screws can be removed after opening the battery compartment, detaching completely from the battery cover. This poses a risk of the screws being swallowed by children, hence the test was not passed.

To address this issue, you can modify the structure of the screws and battery compartment. Ensure that the screws cannot detach from the battery compartment even when fully unscrewed using a tool, and the test can be passed.

Another common issue is the inadequate screw fastening capability. According to ul 4200a-2023 Clause 6.2, for products with battery compartments secured by screws, the screws must endure 10 assembly and disassembly cycles according to the requirements of Table 20 in the UL 60065 standard. The product shown failed the test at 0.85 Nm, as the screws slipped.

Our suggestion for improvement is to increase the screw thread and widen the thread pitch to enhance the screw's grip. If the product uses plastic parts for screw engagement, using hard plastic can increase the gripping force.

If your product needs to undergo ul 4200a testing, feel free to contact JJR Laboratory in China. Our fee is $480.