Nomex Electrical Insulating Paper

Specify the material, not only the brand name

Nomex is a DuPont material family used in electrical insulation applications. An enquiry for Nomex paper should identify the exact grade, thickness and supplied form required by the approved design. Different insulation materials and constructions are not interchangeable simply because they look similar or are described as high-temperature paper.

TPE supplies electrical insulating materials against the purchaser’s specification. Share the grade reference, drawing and application so the proposed material can be checked before supply. Brand and grade availability, dimensions and documentation are confirmed with the enquiry; this page does not establish stock of every Nomex product.

Consider the complete insulation system

The behaviour of an insulating paper depends on its application and the complete insulation system. Mechanical fit, electrical stresses, processing, varnish or resin compatibility and service conditions all matter. A material’s published thermal properties do not by themselves establish the thermal class or suitability of a finished motor or transformer.

For repair work, identify the original design or approved replacement specification. A change in insulation thickness can affect slot space, winding fit and assembly clearances. The designer or responsible repair engineer should approve a substitution instead of treating a similar colour or thickness as proof of equivalence.

Make dimensions and form clear

State whether the requirement is for rolls, sheets or a defined cutting arrangement and provide the required dimensions. Include thickness and any purchaser tolerance or drawing requirement. Specify quantities in a way that allows the offered form to be compared with the workshop’s actual use and waste allowance.

For a winding shop, a clear requirement may include the equipment type, slot or layer application, selected paper grade and processing method. Where the job uses a laminate or a combination of papers and films, identify the complete construction. A single-material paper and a laminate should not be treated as the same item.

Confirm the supply and reference documents

Use the current DuPont documentation for the selected grade and the approved equipment design to review the proposal. State any traceability or test documentation required by your purchasing procedure. A product-family reference photograph helps identify the material group but does not confirm grade, thickness or authenticity.

Send the specified grade, thickness, dimensions, quantity and delivery location to request a quotation. Add a sample reference or drawing when the existing material needs to be identified. If a proposed alternative is discussed, have its construction and compatibility assessed before changing the approved insulation system.

Before requesting a quotation

• Exact grade and approved manufacturer reference
• Required thickness, dimensions and supplied form
• Winding or transformer application and insulation design
• Compatibility with varnish, resin and processing conditions
• Quantity and documentation required by the purchaser

Sources and further reading

DuPont: Nomex paper properties

DuPont: Nomex electrical insulation