In the cathodic dip coating process (CDC) specific threshold values exist for voltage and current density, the exceeding of which results in the desired coating deposit no longer occurring homogeneously across the entire surface of the piece that is to be coated. Instead, the high heat and gas levels result in tearing of the paint or varnish film applied. This is also referred to as exceeding of breakdown voltage. The tears take the form of surface defects (see illustration) in the KTL layer. If the breakdown voltage is too high, depositing therefore results in an unsuitable coating film.