How many #8 THHN fit in 5" PVC Sch 80?
1958 AWG THHN/THWN-2 wires in 5" Rigid PVC conduit, Schedule 80
17.855 sq in × 40 % = 7.1420 sq in allowed. ÷ 0.0366 sq in per wire = 195.14, so 195.
This pull in numbers
- 195 wires fill
- 40.0 % of 5" PVC Sch 80
- Limit for three or more
- 40 %
- For 196 or more
- 6" PVC Sch 80, up to 279
- Pipe to wire diameter
- 22.07 to 1
- In THW insulation
- 163 fit
- In XHHW-2 insulation
- 163 fit
Before you pull 195
- The ground counts. Every wire in the pipe counts toward fill, the green or bare ground and the neutrals too. 195 is the total, not the hots.
- Derating. If all 195 were current-carrying, each would be adjusted to 35 % of its ampacity (Table 310.15(C)(1)): a #8 THHN at 55 A in the 90 °C column becomes 19.3 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.
#8 THHN in other 5" conduit
| Conduit | Inside area | Most #8 THHN |
|---|---|---|
| Rigid metal conduit (RMC, GRC) | 20.212 | 221 |
| Rigid PVC conduit, Schedule 40 | 19.761 | 216 |
| Rigid PVC conduit, Schedule 80 | 17.855 | 195 |
#8 THHN in other PVC Sch 80 sizes
Other wire sizes in 5" PVC Sch 80
#8: 195#6: 141#4: 86#3: 73#2: 61#1: 45#1/0: 38#2/0: 32#3/0: 26#4/0: 22250 kcmil: 18300 kcmil: 15350 kcmil: 13500 kcmil: 10