A meticulous and systematic approach to applying the electrostatic discharges is essential for comprehensive testing and valid outcomes. This section details the precise sequence of operations, from EUT configuration to the application of discharges.

4.1 Pre-Test EUT Configuration

Energize the EUT with its appropriate auxiliary power and apply input energizing quantities according to its rated values. The value of the input quantity should be set as close as possible to the transitional (operate/non-operate) state, but not closer than the claimed variation due to electrostatic discharge as declared by the manufacturer. This ensures the EUT is in a sensitive state where any potential maloperation can be readily detected.

4.2 Selection of Test Points

To achieve reproducible results, test points should be selected as recommended by the manufacturer. These points must be accessible to the operator under normal service conditions and should include the following:

• Knobs, push-buttons, switches, terminals, etc.
• Points on covers of insulating material where conducting parts are located close to the inside of the cover.
• Points on conducting parts not belonging to the EUT but located in its vicinity, particularly when the EUT has an insulating cover.

4.3 Discharge Application Sequence

Apply the electrostatic discharges according to the following standardized sequence:

1. Adjust the test voltage of the discharge generator to the level of the chosen test severity class.
2. Perform the test using single discharges.
3. Apply at least 10 single discharges with positive polarity to each selected test point.
4. Apply at least 10 single discharges with negative polarity to each selected test point.
5. Maintain a recommended time interval of at least 1 second between successive discharges. Longer intervals may be necessary to properly observe the EUT and determine if a failure has occurred.

Note: For exploratory purposes to efficiently identify sensitive test points, the standard permits the use of a higher repetition rate (e.g., 20 discharges per second). However, the formal test to verify compliance must be performed using single discharges as specified above.

4.4 Test Execution Methods

The standard defines two methods for applying the discharge, with a clear preference for the contact discharge method where applicable.

4.4.1 Contact Discharge Method (Preferred)

1. Apply this method to all conductive surfaces of the EUT.
2. Hold the discharge generator perpendicular to the surface under test.
3. Touch the tip of the discharge electrode to the EUT.
4. Operate the discharge switch on the generator to apply the discharge.

Note on Coated Surfaces: For conductive surfaces covered with paint or another coating, the procedure is as follows:

• If the manufacturer does not declare the coating to be insulating, the pointed tip of the generator must penetrate the coating to make firm contact with the underlying conductive substrate.
• If the manufacturer does declare the coating to be insulating and its withstand voltage exceeds the test voltage, the contact discharge test shall not be applied. In this case, the air discharge method should be used to test these surfaces.

4.4.2 Air Discharge Method

1. Use this method only when accessible surfaces of the EUT are non-conducting.
2. Hold the charged discharge generator perpendicular to the surface under test.
3. Approach the tip of the discharge electrode to the EUT as fast as possible without causing mechanical damage to create a spark.
4. After each discharge, remove the electrode from the EUT and allow the generator to retrigger for the next discharge.

Following the diligent execution of these procedures, the final and most important phase is the evaluation of the results against the standard’s acceptance criteria.