Switch-mode and other power supplies for automatic data processing (ADP) machines are explicitly covered by subheading 850440 (Static Converters & ADP Power Supplies). They are not classified with the computer or peripheral they power. The key is that the power supply is a separate article, not an integral part of a presented ADP unit.

Large liquid dielectric power transformers have been the subject of Section 232 national-security investigations and related executive actions. The applicable measure and its scope depend on the specific tariff line and country of origin; importers of high-KVA transformers should verify current order status and any applicable exclusions before entry.