How many 250 kcmil THHN fit in 6" PVC Sch 80?
25250 kcmil THHN/THWN-2 wires in 6" Rigid PVC conduit, Schedule 80
25.598 sq in × 40 % = 10.2392 sq in allowed. ÷ 0.3970 sq in per wire = 25.79, so 25.
This pull in numbers
- 25 wires fill
- 38.8 % of 6" PVC Sch 80
- Limit for three or more
- 40 %
- For 26 or more
- no bigger PVC Sch 80
- Pipe to wire diameter
- 8.03 to 1
- In THW insulation
- 22 fit
- In XHHW-2 insulation
- 26 fit
Before you pull 25
- The ground counts. Every wire in the pipe counts toward fill, the green or bare ground and the neutrals too. 25 is the total, not the hots.
- Derating. If all 25 were current-carrying, each would be adjusted to 45 % of its ampacity (Table 310.15(C)(1)): a 250 kcmil THHN at 290 A in the 90 °C column becomes 130.5 A. Grounds don't count as current-carrying. How derating works
- Bends. A full pipe pulls hard. Keep to 360° of bends between pull points, less for a tight fill.
250 kcmil THHN in other 6" conduit
| Conduit | Inside area | Most 250 kcmil THHN |
|---|---|---|
| Rigid metal conduit (RMC, GRC) | 29.158 | 29 |
| Rigid PVC conduit, Schedule 40 | 28.567 | 28 |
| Rigid PVC conduit, Schedule 80 | 25.598 | 25 |
250 kcmil THHN in other PVC Sch 80 sizes
Other wire sizes in 6" PVC Sch 80
#4: 124#3: 105#2: 88#1: 65#1/0: 55#2/0: 46#3/0: 38#4/0: 31250 kcmil: 25300 kcmil: 22350 kcmil: 19500 kcmil: 14