How many #8 THHN fit in 3" Liquidtight?
818 AWG THHN/THWN-2 wires in 3" Liquidtight flexible metal conduit (LFMC)
7.475 sq in × 40 % = 2.9900 sq in allowed. ÷ 0.0366 sq in per wire = 81.69, so 81.
This pull in numbers
- 81 wires fill
- 39.7 % of 3" Liquidtight
- Limit for three or more
- 40 %
- For 82 or more
- 3-1/2" Liquidtight, up to 106
- Pipe to wire diameter
- 14.28 to 1
- In THW insulation
- 68 fit
- In XHHW-2 insulation
- 68 fit
Before you pull 81
- The ground counts. Every wire in the pipe counts toward fill, the green or bare ground and the neutrals too. 81 is the total, not the hots.
- Derating. If all 81 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 3" conduit
| Conduit | Inside area | Most #8 THHN |
|---|---|---|
| Electrical metallic tubing | 8.846 | 96 |
| Intermediate metal conduit | 7.922 | 86 |
| Rigid metal conduit (RMC, GRC) | 7.499 | 82 |
| Rigid PVC conduit, Schedule 40 | 7.268 | 79 |
| Rigid PVC conduit, Schedule 80 | 6.442 | 70 |
| Flexible metal conduit (FMC, Greenfield) | 7.069 | 77 |
| Liquidtight flexible metal conduit (LFMC) | 7.475 | 81 |
#8 THHN in other Liquidtight sizes
Other wire sizes in 3" Liquidtight
#10: 141#8: 81#6: 59#4: 36#3: 30#2: 26#1: 19#1/0: 16#2/0: 13#3/0: 11#4/0: 9250 kcmil: 7300 kcmil: 6350 kcmil: 5500 kcmil: 4