IEC stands for International Electrotechnical Commission and is an international standards organization for standards in the field of electrical engineering and electronics based in Geneva.
UL and IEC differ significantly from each other. IEC standards specify only the minimum safety requirements of a device or system, whereas the technical details of the design implementation of the safety requirements are left to the manufacturer. UL's guidelines, on the other hand, are far more detailed in terms of product safety and application. In addition to drafting standards, UL is also responsible for approval or general third-party certification as well as on-site acceptance. For example, there are factory inspections of equipment manufacturers to ensure that the framework conditions established with the certification are met. Product modifications must be approved by UL before manufacturing begins.
In IEC applications, it is sufficient if the device characteristics (utilization category) match the load. In UL, on the other hand, the application in which the devices are used is of additional importance. Different applications are subject to different guidelines.