This part of GB/T 5169 specifies the ball pressure test, which is one of the methods for testing the heat resistance of non-metallic materials. This standard applies to electrical equipment and its components and parts, and also applies to solid electrical insulating materials other than ceramics.
GB/T 5169.21-2006 Referenced Document
GB/T 11026.4-1999 Guide for the determination of thermal endurance properties of electrical insulating materials-Part 4: Ageing ovens-Single-chamber ovens
ISO 3290:2001 Rolling bearings - Balls - Dimensions and tolerances
GB/T 5169.21-2006 history
2017GB/T 5169.21-2017 Fire hazard testing for electric and electronic products.Part 21:Abnormal heat.Ball pressure test method
2006GB/T 5169.21-2006 Fire hazard testing for electric and electronic products.Part 21:Abnormal heat.Ball pressure test