How many 350 kcmil THHN fit in 4" Liquidtight?
9350 kcmil THHN/THWN-2 wires in 4" Liquidtight flexible metal conduit (LFMC)
12.692 sq in × 40 % = 5.0768 sq in allowed. ÷ 0.5242 sq in per wire = 9.68, so 9.
This pull in numbers
- 9 wires fill
- 37.2 % of 4" Liquidtight
- Limit for three or more
- 40 %
- For 10 or more
- no bigger Liquidtight
- Pipe to wire diameter
- 4.92 to 1
- In THW insulation
- 8 fit
- In XHHW-2 insulation
- 10 fit
Before you pull 9
- The ground counts. Every wire in the pipe counts toward fill, the green or bare ground and the neutrals too. 9 is the total, not the hots.
- Derating. If all 9 were current-carrying, each would be adjusted to 70 % of its ampacity (Table 310.15(C)(1)): a 350 kcmil THHN at 350 A in the 90 °C column becomes 245 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.
350 kcmil THHN in other 4" conduit
| Conduit | Inside area | Most 350 kcmil THHN |
|---|---|---|
| Electrical metallic tubing | 14.753 | 11 |
| Intermediate metal conduit | 13.631 | 10 |
| Rigid metal conduit (RMC, GRC) | 12.882 | 10 |
| Rigid PVC conduit, Schedule 40 | 12.554 | 9 |
| Rigid PVC conduit, Schedule 80 | 11.258 | 8 |
| Flexible metal conduit (FMC, Greenfield) | 12.566 | 9 |
| Liquidtight flexible metal conduit (LFMC) | 12.692 | 9 |
350 kcmil THHN in other Liquidtight sizes
Other wire sizes in 4" Liquidtight
#8: 138#6: 100#4: 61#3: 52#2: 44#1: 32#1/0: 27#2/0: 23#3/0: 19#4/0: 15250 kcmil: 12300 kcmil: 11350 kcmil: 9500 kcmil: 7