Contact discharge shall be applied to the conductive surfaces of the EUT and to coupling planes and air discharges shall be applied at insulating surfaces.

In case of metallic enclosure, contact discharges shall be the preferred method due to its better reproducibility. In case of plastic enclosure, air discharges shall be applied to points such as switches, knobs, buttons, indicators, LEDs, slots, grilles, since a clearance may be a discharge path into the equipment internal conductor.