Power 101: IEC 60335-1 Explained

Appliances were once relatively simple machines, but with the evolution of the IoT and smart homes, they now have graphical displays, wireless connectivity, and other features often associated with ITE applications. These new capabilities make safety more important than ever and IEC 60335-1 is the safety standard that covers household appliances. So how does it compare to the ubiquitous IEC 60950 standard?

The first difference is in creepage and clearance distances, which are based on the working voltage and insulation type. In many instances, the requirements are the same, but there are some differences. For example, with reinforced installation and a working voltage between 250 and 300 volts, IEC 60950-1 requires 6.4 millimeters of creepage and 4 millimeters of clearance. For the same conditions, IEC 60335-1 increases the creepage requirement to eight millimeters, but decreases the clearance requirement to 3.5 millimeters. For isolation voltage, IEC 60950-1 defines fixed values for input to output, while IEC 60335-1 has an input to output requirement that is 2.4 kv, plus the working voltage multiplied by 2.4. For leakage current, IEC 60950-1 defines just two categories: portable appliances, which are limited to 0.75 milliamps, and stationary appliances, which are limited to 3.5 milliamps.