Clearance and creepage distances are covered in many standards, and their requirements may be different. Because different electrical equipment may have different requirements for electrical clearances and creepage distances. Even different parts of the same equipment may have different requirements for electrical clearances and creepage distances.
The above description is based on the regulations on electrical clearance and creepage distance for specific electrical products. If you want to understand the basic principles for determining insulation size and practical application in terms of electrical insulation coordination, you can refer to the following series of standards (low-voltage systems):
GB/T 16935.1-2008 Insulation coordination of equipment in low-voltage systems Part 1 : Principles, requirements and tests
GB/Z 16935.2-2013 Insulation coordination of equipment in low-voltage systems Part 2-1: Application guide GBT 16935 series application explanation, sizing examples and dielectric tests
GB/T 16935.3-2005 Insulation coordination of equipment in low-voltage systems Part 3: Anti-fouling protection by coating, canning and molding
GB/T 16935.4-2011 Equipment in low-voltage systems Insulation coordination Part 4: High-frequency voltage stress considerations
GB/T 16935.5-2008 Insulation coordination of equipment in low-voltage systems Part 5: Determination of electrical clearances and creepage distances not exceeding 2mm