Transformer Pressboard
High-density pressboard weighing over 225 g/m², made from compressed wood fibers, used as insulation in oil-immersed electrical transformers. It falls under HTS 4805.93.20.00 as uncoated pressboard, not further worked beyond note 3 specifications, in sheets for electrical applications.
Import Duty Rates by Country of Origin
Alternative Classifications
This product could be classified differently depending on its characteristics or intended use.
If containing fibers obtained by a mechanical process
Mechanical pulp content over specified thresholds shifts classification to heading 4805 subheading for fluting or other papers.
If waterproofed or treated with plasticizers
Any surface coating or impregnation beyond basic pressing makes it 'paperboard coated on one or both sides' under 4811.
If molded into specific shapes like gaskets
Further working into articles like electrical components classifies as 'other paper machinery parts' excluding pressboard sheets.
Not sure which classification is right?
The Tariff Assistant works through the GRI rules on your specific product to reach the right HTS code — and can price the duty on it in the same conversation.
Import Tips & Compliance
• Verify grammage exceeds 225 g/m² via lab testing; customs may require certification to confirm pressboard specs
• Provide end-use declaration for electrical insulation to avoid reclassification; include transformer manufacturer specs
• Watch for moisture content limits under 8% to prevent mold issues during transit; common pitfall is improper packing
Related Products under HTS 4805.93.20.00
High-Density Insulation Pressboard
Uncoated pressboard sheets >225 g/m², high density 1.25 g/cm³, for switchgear insulation and panel boards in power distribution. Fits 4805.93.20.00 as pressboard in rolls/sheets, no additional working.
Virgin Pulp Pressboard
100% virgin softwood pulp pressboard, 400 g/m² sheets for high-strength electrical applications. Classed in 4805.93.20.00 as other uncoated pressboard over specified weight.
Electrical Presspahn Board
Presspahn is a specialized pressboard from 100% sulfate wood pulp, density 1.0-1.2 g/cm³, over 225 g/m², in sheets for dielectric insulation in high-voltage equipment. Classified under 4805.93.20.00 as uncoated pressboard meeting chapter note 3, ideal for motors and generators.
Density Pressboard Grade A
Grade A density pressboard, 225-500 g/m², compressed to 1.1 g/cm³ min, uncoated sheets for battery separators and electrical insulation. HTS 4805.93.20.00 covers this as 'other' pressboard not further processed per note 3.
Sulfate Process Pressboard Sheets
Pressboard from chemical sulfate pulp, 300 g/m², machine-pressed sheets for marine electrical panels. HTS 4805.93.20.00 for other uncoated pressboard ≥225 g/m², aligning with kraft-like strength.
Battery Separator Pressboard
Specialty pressboard >225 g/m² for lead-acid battery separators, high purity sulfate pulp, uncoated. Under 4805.93.20.00 as pressboard not further worked, essential for industrial batteries.