The specifications of the terminals products manufactured in Europe using the IEC standards, products manufactured in the United States UL standards. In determining the power and performance of the terminals specifications and there is no uniform standard, so users need to understand the difference between the UL and IEC specifications.

The difference between these two standards is very large. Do not understand the product specifications measurement method engineers will take a considerable risk, because the optional device may be up to less than the required power level, far beyond the need for design or selection device specifications. In Europe, the current rating of the device is increased by monitoring the current determined by the temperature of the metallic conductor. Measurement as it will be when the current When metal pin temperature higher than the ambient temperature of 45 ° C, the rated current of the device (or the maximum current value). IEC specifications another is permitted current value, which is 80% of the maximum current. Unlike this, UL standards will allow the metal conductor temperature than the ambient temperature higher than 30 ° C when 90% of the current value as the device of the current nominal value.

Thus, the temperature of the metallic conductor portion are a very important factor in all applications. This is even more important for industrial equipment. Industrial equipment often need to work in temperatures up to 80 ° C environment. If the temperature of the terminals 30 ℃ or 45 ° C higher than this temperature, then the temperature of the terminals will be more than 100 ° C. According to the selected type of device uses the nominal value of, and the insulating material, the product must be less than the rating of the current work, so as to guarantee that they can work reliably in the desired temperature range. Sometimes, material suitable for compact package devices may not be able to satisfy the cooling requirements, and therefore such must be significantly lower than the rated current terminals devices. So, it reflects the importance of how to select the terminal block.

With corporate globalization, the need to design in global sales system, so system designers are increasingly frequent use of power terminal products produced in other countries. Nominal value measurement method used in Europe, the device design is lower than the nominal value is a common practice in Europe. However, many designers are not familiar with this concept, if the understanding of the differences between the respective standard, and will be difficulties in the design process.