LE Phenolic Sheet — Thicknesses, Sizes & Stock Forms
LE phenolic sheet is flat laminate plate stock produced from NEMA Grade LE linen phenolic: fine-weave cotton (linen) fabric layers saturated with phenolic resin and compression-molded into rigid thermoset sheet. Ready Plastics stocks LE phenolic sheet for terminal boards, switchgear insulating panels, bushing plates, and precision electrical assemblies where a smooth surface finish, high dielectric performance, and stable dimensions under varying humidity are required. NEMA LI-1 governs Grade LE.
At a glance:
- Thickness range: 0.020" to 4.0"
- Standard sheet size: 48" × 96" (4 ft × 8 ft); cut-to-size available
- Flatness tolerance: per NEMA LI-1; thickness tolerance ±10% standard
- Material: NEMA Grade LE — fine-weave cotton-fabric phenolic laminate (NEMA LI-1)
- Production method: Compression-molded thermoset laminate
- Color: Natural tan
Standard Thickness Table
LE phenolic sheet is stocked in the following standard thicknesses:
| Thickness | Sheet Size | Notes |
|---|---|---|
| 0.020"–0.062" | 48" × 96" | Thin sheet for precision shims and gaskets |
| 0.093" (3/32") | 48" × 96" | Light insulator barrier stock |
| 0.125" (1/8") | 48" × 96" | Standard terminal board stock |
| 0.250" (1/4") | 48" × 96" | Panel insulator and bushing plate |
| 0.375" (3/8") | 48" × 96" | Structural insulating plate |
| 0.500" (1/2") | 48" × 96" | Heavy-duty panel stock |
| 0.750" (3/4") | 48" × 96" | Thick insulating plate |
| 1.000"–4.000" | 48" × 96" | Thick plate for machined electrical parts |
Cut-to-size is available on all thicknesses; minimum order is one piece.
Mechanical & Electrical Properties
LE phenolic sheet carries the full NEMA Grade LE property set per NEMA LI-1:
| Property | Value |
|---|---|
| Tensile strength | 36,000 psi (245 MPa) |
| Flexural strength (LW, 0.125") | 18,000 psi (120 MPa) |
| Compressive strength | 13,000 psi (89 MPa) |
| Shear strength | 13,500 psi (93 MPa) |
| Bond strength | 1,900 psi (13 MPa) |
| M-scale hardness | 100 |
| Izod impact strength at 49 °C (LW) | 1.35 ft·lb/in |
| Specific gravity | 1.34 |
| Water absorption (24 hr) | 1.8% |
| Flammability | UL 94HB |
| Max. operating temperature | 255 °F (125 °C) |
The lower water absorption (1.8%) compared to CE (2.0%) means LE sheet maintains tighter dielectric consistency in environments with fluctuating humidity — important for open switchgear and outdoor-rated panels.
Typical Applications
- Terminal boards and terminal strips — LE sheet is the standard material for screw-terminal insulator strips in control panels and junction boxes
- Switchgear and MCC insulating panels — Flat sheet cuts to custom shapes for bus-bar supports, arc barriers, and phase separators
- Bushing plates and flange insulators — LE's smooth surface and consistent thickness support precision gasket and flange insulator applications
- Transformer coil formers — Flat LE sheet forms into wound coil insulation layers for dry-type transformer construction
- Precision test fixture plates — Stable dimensions and good dielectric properties make LE sheet a reliable base for high-voltage test fixtures and probe boards
- Relay and contactor mounting substrates — Low water absorption keeps insulating resistance stable in relay enclosures subject to condensation
Machining LE Phenolic Sheet
LE phenolic sheet saws cleanly on circular saws and CNC routers with carbide-tipped blades; the fine linen weave produces a smoother cut edge than canvas grades with the same tooling. Use a backer board when drilling thin sheet to prevent backside tear-out. Milling and routing produces crisp edges suitable for close-tolerance stacking in transformer and switchgear assemblies. Surface grinding is practical for flatness-critical applications. Phenolic dust is abrasive — dust extraction and respiratory protection are required throughout.
Related
- LE Phenolic Grade Line Card
- LE Phenolic Rod — round bar stock for precision turned electrical insulators
- LE Phenolic Tube — hollow section for insulating sleeve and conduit applications
- CE Phenolic Sheet — coarse canvas grade for general-purpose insulating panels