Grounded conductor

General Discussion
#1

Hello experts,

Does a grounded conductor pose a risk to an Electrostatic Discharge Sensitive (ESDS) item?
What would be the limits implicated on this?

Thank you

#2

Santiago,

One of the fundamental ESD control principles listed in ANS/ESD S20.20 is to ground all conductors. When conductors cannot be grounded, they need to be maintained < +/- 35V.

Still, a grounded conductor can pose a risk to an ungrounded ESDS item. That is the principal idea in the Charged Device Model (CDM). That is why it is recommended to use dissipative ESDS control items whenever possible. If the ESDS items can become charged, then contact with a dissipative surface will result in a more controlled discharge that should not damage it.

Footnote 9 of ANSI/ESD S20.20 states: “If there is a concern for CDM failures, then a lower limit of 1.0 x 10^6 ohms for point to point and point to groundable point should be considered.”

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#3

Thank you very much!