IEC Versus ANSI/UL Medium-Voltage Motor Control: Which One Should You Use and Does It Matter?

Most companies engaged in the oil, gas, and chemicals sector have global operations. For simplicity, commonality, and increased reliability of operations and for economies of scale in procurement, the companies prefer to buy common products across all operations. When it comes to medium-voltage motor control centers, the issue of which standard to follow then becomes critical with the IEC and UL ones being most common. An increasing degree of commonality can be seen in these standards. It is an opportune time to revisit the topic of whether it matters which set of standards is followed. In this article, we cover the key similarities and differences between UL 347 and the IEC 62271-1, -200, and -106 standards and see what the implications are for the applications seen in our industry. To-date, no such review is available in published technical literature.