Hello! JohnK
Annotations on workbenches in ANSI/ESD S20.20（Due to a wide variety of applications for worksurfaces, specific requirements that could be broadly applied are difficult to determine. If there is a concern for CDM failures, then a lower limit of 1.0 x 106 ohms for point to point and point to groundable point should be considered.）
Annotations on workbenches in IEC61340-5-1( In situations where charged device model (CDM) damage is a concern, a minimum point to point resistance limit of 1 × 104 Ω is recommended.)
Why are there such significant differences between the two standards, and will there be a unified standard in the future？
This has been an interesting topic in the two meetings. While different, there is not much significance in the numbers. The requirements in both standards for worksurfaces is 0 to 1x10e9 ohms. The note represents a slight difference of opinion in the two groups and what is considered to be “safe” from CDM events.
Personally, I don’t think it makes much differenence between the two numbers. The IEC spec allows for slightly more materials. The ANSI/ESD spec keeps the definitions between conductive and dissipitive (for floors for example) loosely linked. Since these are recommendations, I’m not sure if the differences would be resolved in the next versions of the two standards.