IEC 61000-4-2 states that “the preferred test method is the contact discharge method, and the air discharge method is used when the contact discharge method cannot be applied.” Specifically, how should this be determined?

For general electronic equipment, contact discharge testing is performed on screws used to fasten the enclosure, metal parts of a metal enclosure (using a conical tip to pierce the coating and make contact with the metal),

and metal shells of interface connectors, etc.

Also, because IEC 61000-4-2 is a standard defined at the system level, electrostatic discharge is not applied directly to components on the board or to transmission lines.

Application points in air discharge testing include resin parts, the entire front surface of LCD screens, gaps in the enclosure, ventilation holes, and other locations where the surface is insulated.

The discharge is applied with the expectation that it will discharge from gaps in a resin enclosure to the internal metal chassis or printed circuit board.

The explanation “gaps in the enclosure, etc.” is not included in Ed.2. It is planned to be included in Ed.3.