To ensure reproducibility, the standard defines a strict laboratory test set-up and a detailed procedure for applying the discharges.

4.1. Test Environment and Set-up

• Location: Tests must be conducted in a laboratory under the environmental reference conditions outlined in IEC 255-6.
• Ground Reference Plane (GRP): A metallic sheet (copper or aluminum) of at least 0.25 mm thickness must be used. Its size must project beyond the EUT by at least 0.5 m on all sides. The GRP must be connected to the protective earth system.
• EUT Placement: The equipment shall be placed on an insulating support of 0.1 m thickness above the GRP.
• Cabling: Interconnecting cables must be kept at a distance of at least 0.1 m from the GRP. The discharge generator must be earthed via its discharge return cable directly to the GRP, with the total length of this cable being 2 m.

4.2. Test Procedure

1. Test Points Selection: Points for discharge application are those accessible to an operator under normal service conditions. These include:
   • Knobs, push-buttons, switches, terminals, etc.
   • Points on insulating covers that are in close proximity to conductive parts inside the equipment.
   • Settings adjustments that require cover removal are not included.
2. EUT Energization: The EUT must be energized with auxiliary energizing quantities and loaded according to its specifications. The value of the input energizing quantity should be set as close as possible to the transitional state (e.g., just below the operate value).
3. Application of Discharges:
   • The test must be performed with single discharges.
   • Each selected test point must be subjected to at least 10 discharges with positive polarity and 10 discharges with negative polarity.
   • The recommended time interval between successive discharges is 1 second.
   • The generator must be held perpendicular to the surface being tested.
4. Specific Methodologies:
   • Contact Discharge: The tip of the discharge electrode must touch the EUT before the discharge switch is activated.
   • Air Discharge: The tip of the electrode should approach the EUT as fast as possible without causing mechanical damage. After each discharge, the electrode is removed and the generator is retriggered.
   • Coated Surfaces: If a coating is declared insulating, air discharge tests are used. If not, the contact discharge probe must penetrate the coating to make contact with the conductive substrate.