XHHW Wire Fill Chart
XHHW and XHHW-2 maximum conductors across every conduit type — EMT, IMC, RMC, PVC Sch 40, PVC Sch 80, FMC, LFNC, and ENT — NEC 2023.
XHHW (cross-linked polyethylene) wire fill chart values are identical to THHN at the same gauge — NEC Table 5 lists them with the same cross-sectional area. The difference is insulation chemistry, not fill. For mixed-gauge installations, use the conduit fill calculator.
- 1/2" EMT—
- 3/4" EMT—
- 1" EMT—
- 1-1/4" EMT—
- 1-1/2" EMT—
- 2" EMT—
- 2-1/2" EMT—
- 3" EMT—
- 3-1/2" EMT—
- 4" EMT—
| TRADE → WIRE ↓ | 1/2" | 3/4" | 1" | 1-1/4" | 1-1/2" | 2" | 2-1/2" | 3" | 3-1/2" | 4" |
|---|---|---|---|---|---|---|---|---|---|---|
| 14 AWG | — | — | — | — | — | — | — | — | — | — |
| 12 AWG | — | — | — | — | — | — | — | — | — | — |
| 10 AWG | — | — | — | — | — | — | — | — | — | — |
| 8 AWG | — | — | — | — | — | — | — | — | — | — |
| 6 AWG | — | — | — | — | — | — | — | — | — | — |
| 4 AWG | — | — | — | — | — | — | — | — | — | — |
| 3 AWG | — | — | — | — | — | — | — | — | — | — |
| 2 AWG | — | — | — | — | — | — | — | — | — | — |
| 1 AWG | — | — | — | — | — | — | — | — | — | — |
| 1/0 | — | — | — | — | — | — | — | — | — | — |
| 2/0 | — | — | — | — | — | — | — | — | — | — |
| 3/0 | — | — | — | — | — | — | — | — | — | — |
| 4/0 | — | — | — | — | — | — | — | — | — | — |
| 250 | — | — | — | — | — | — | — | — | — | — |
| 300 | — | — | — | — | — | — | — | — | — | — |
| 350 | — | — | — | — | — | — | — | — | — | — |
| 400 | — | — | — | — | — | — | — | — | — | — |
| 500 | — | — | — | — | — | — | — | — | — | — |
| 600 | — | — | — | — | — | — | — | — | — | — |
| 700 | — | — | — | — | — | — | — | — | — | — |
| 750 | — | — | — | — | — | — | — | — | — | — |
| 800 | — | — | — | — | — | — | — | — | — | — |
| 900 | — | — | — | — | — | — | — | — | — | — |
| 1000 | — | — | — | — | — | — | — | — | — | — |
EMT — Electrical Metallic Tubing × XHHW (90°C dry) · NEC 2023 Ch.9 Tables 4 & 5 · 40% (3+), 31% (2), 53% (1)
NOTES & CONTEXT
What is XHHW?
Cross-linked polyethylene (XLPE) insulation, single-layer (no nylon jacket). XHHW is rated 90°C dry; XHHW-2 adds 90°C wet rating. Common in solar PV, high-ambient industrial, and where long outdoor service life matters more than initial cost.
XHHW vs THHN — same fill, different insulation
NEC Chapter 9 Table 5 lists THHN, THWN-2, XHHW, and XHHW-2 with identical cross-sectional areas. So switching from THHN to XHHW does not change your conduit fill count. See THHN vs XHHW comparison.
When to specify XHHW-2 over THHN/THWN-2
- Solar PV array circuit wiring (UV resistance, decades of outdoor service)
- High ambient temperature continuous operation (40°C+)
- Chemical / oil environments where XLPE outperforms PVC
- Long-term ageing requirements
Pulling considerations
XHHW has no nylon outer jacket, so its surface friction during a pull is slightly higher than THHN. Use generous lubricant and limit pulling tension per Southwire or manufacturer recommendations. For very tight fill near 40%, THHN may be the easier pull.