Cotton phenolic Grade LE is a thermoset laminate combining fine-weave linen fabric with phenolic resin, cured under heat and pressure into rigid le phenolic sheet and rod stock. Governed by NEMA LI-1, it is the highest-performing electrical grade in the cotton phenolic family — delivering both high dielectric insulation and the precision machinability of a fine-linen construction, making it the preferred choice for electrical components that must also be machined to tight tolerances.
Grade LE achieves 36,000 psi tensile strength, 18,000 psi flexural strength, and 13,000 psi compressive strength with a Rockwell M100 hardness and water absorption of only 1.8% over 24 hours — a low figure that supports stable dielectric performance in humid environments. Maximum continuous operating temperature is 255°F (125°C). The fine linen weave yields a smooth, consistent surface that machines cleanly into terminal boards, electrical bushings, spacers, switchgear components, and other precision electrical parts.
Standards. Grade LE is governed by NEMA LI-1. Flammability is rated 94HB per UL 94. Test methods follow ASTM D709. The le grade designation specifically identifies fine-linen reinforcement with an electrical rating — the combination that distinguishes LE from the mechanical-only linen grade (L) and the canvas electrical grade (CE).
Sister grades. Choose Grade L — linen phenolic, mechanical grade when dielectric performance is not required and you want the same fine surface and machinability at lower cost. Step across to Grade CE — canvas phenolic, electrical grade when you need higher impact strength in an electrical-rated grade. For the highest dielectric strength across all cotton phenolic grades, LE is the top choice; for even higher dielectric demands, see Grade C comparisons or glass-epoxy laminates.
