XX Phenolic Tube — IDs, ODs, Wall Thicknesses & Lengths
XX phenolic tube is hollow cylindrical stock produced from NEMA Grade XX paper phenolic laminate — layers of kraft paper saturated with phenolic resin and wound or compression-molded into tube form. Ready Plastics stocks XX phenolic tube as economical insulating sleeve, conduit liner, and spacer tube stock for switchboard, control panel, and general electrical applications where lightweight construction and reliable dielectric insulation matter more than high mechanical toughness. NEMA LI-1 governs Grade XX.
At a glance:
- OD range: approximately 0.375" to 6.0"
- Wall thickness: standard walls from 0.062" to 0.500"+
- Standard length: 48" (4 ft) per piece; cut-to-length available
- Tolerances: OD ±0.010", ID ±0.015" typical
- Material: NEMA Grade XX — kraft-paper phenolic laminate (NEMA LI-1)
- Production method: Wound or compression-molded thermoset
- Color: Natural tan to light brown
Standard Tube Size Table
XX phenolic tube is stocked in representative sizes:
| OD | Wall Thickness | ID (approx.) | Standard Length |
|---|---|---|---|
| 0.500" | 0.062" | 0.376" | 48" |
| 0.750" | 0.093" | 0.564" | 48" |
| 1.000" | 0.125" | 0.750" | 48" |
| 1.250" | 0.125" | 1.000" | 48" |
| 1.500" | 0.187" | 1.126" | 48" |
| 2.000" | 0.250" | 1.500" | 48" |
| 3.000" | 0.375" | 2.250" | 48" |
| 4.000" | 0.500" | 3.000" | 48" |
Non-standard OD/wall combinations available on request. Minimum order is one piece cut-to-length.
Mechanical & Electrical Properties
XX phenolic tube properties derive from the NEMA Grade XX laminate per NEMA LI-1:
| Property | Value |
|---|---|
| Tensile strength | 35,000 psi (240 MPa) |
| Flexural strength (LW, 0.125") | 34,000 psi (230 MPa) |
| Compressive strength | 17,000 psi (115 MPa) |
| Shear strength | 11,500 psi (79 MPa) |
| Bond strength | 1,500 psi (10 MPa) |
| M-scale hardness | 120 |
| Specific gravity | 1.35 |
| Water absorption (24 hr) | 2.00% |
| Flammability | UL 94HB |
| Max. operating temperature | 280 °F (140 °C) |
High compressive strength (17,000 psi) and high Rockwell M 120 hardness mean XX tube resists radial crushing loads better than many thermoplastic alternatives at similar wall thickness. The maximum operating temperature of 280 °F (140 °C) exceeds cotton phenolic tube grades.
Typical Applications
- Conductor insulating sleeves — XX phenolic tube provides bus-bar and conductor pass-through insulation in low-voltage switchboards and panel boards
- Transformer coil bobbins — Wound paper-phenolic tube forms the structural bobbin for wire coils in distribution and control transformers
- Control panel conduit inserts — Short-cut XX tube sections line panel knock-outs and conduit entries to insulate wiring from metal enclosure edges
- Spacer columns in electrical assemblies — Pre-cut XX tube maintains precise component spacing and electrical clearance in relay racks and MCC bays
- Drum and spool cores — Lightweight specific gravity (1.35) and good compressive strength suit XX tube as winding spool cores for wire and cable
- Switchboard bushing sleeves — Economical XX tube supports conductor-to-ground isolation in residential and commercial switchboard bushing applications
Machining XX Phenolic Tube
XX phenolic tube turns on a lathe using carbide tooling with the same ease as XX sheet stock. The paper-base laminate machines to smooth OD and bore finishes without the fabric fiber tear-out that can occur on cotton grades. Support thin-wall XX tube with a closely fitting mandrel or plug to prevent wall collapse under chuck pressure. Cross-drilling and radial slotting are practical; exit burrs are minimal compared to woven-fabric grades. Phenolic dust is abrasive — use dust extraction and respiratory protection throughout all machining operations.
Related
- XX Phenolic Grade Line Card
- XX Phenolic Rod — solid round stock for switchboard pins and machined insulator blanks
- XX Phenolic Sheet — flat plate for switchboard panels and control panel substrates
- X Phenolic — lower-grade paper phenolic for general non-critical insulating applications