SAFETY REQUIREMENTS
When a product has to be recognized by a certain safety agency, there may be a legal requirement to meet specific insulations listed in the relevant agency's standard. In this case, finding the required spacing is more or less straightforward. For example, in the U.S. for most mains-powered or battery-powered information technology equipment, the minimum allowed PCB spacing should be determined from UL 60950-1 2nd Edition Tables 2K, 2L, 2M or 2N. These tables specify so-called clearance and "creepage" distances for various grades of insulation as functions of working voltage, pollution degree, PCB material group and coating.