What HS code is used for transformer oil in trade?

Transformer oil is commonly classified under HS heading 2710 for petroleum oils and oils obtained from bituminous minerals, not elsewhere specified, with national subheadings varying by country and whether the oil is new, inhibited, or specially prepared. Many customs schedules place mineral insulating oils under 2710 with local statistical suffixes. Always confirm the exact code with your broker and product description to match your jurisdiction’s tariff schedule and documentation requirements.