How many #4/0 THHN fit in 2" Flex?
44/0 AWG THHN/THWN-2 wires in 2" Flexible metal conduit (FMC, Greenfield)
3.269 sq in × 40 % = 1.3076 sq in allowed. ÷ 0.3237 sq in per wire = 4.04, so 4.
This pull in numbers
- 4 wires fill
- 39.6 % of 2" Flex
- Limit for three or more
- 40 %
- For 5 or more
- 2-1/2" Flex, up to 6
- Pipe to wire diameter
- 3.18 to 1
- In THW insulation
- 3 fit
- In XHHW-2 insulation
- 4 fit
The pipe is 3.18 times the wire's diameter, inside the 2.8 to 3.2 range where three wires can wedge side by side on a pull. If you pull exactly three, go up a size or pull with care.
Before you pull 4
- The ground counts. Every wire in the pipe counts toward fill, the green or bare ground and the neutrals too. 4 is the total, not the hots.
- Derating. If all 4 were current-carrying, each would be adjusted to 80 % of its ampacity (Table 310.15(C)(1)): a #4/0 THHN at 260 A in the 90 °C column becomes 208 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.
#4/0 THHN in other 2" conduit
| Conduit | Inside area | Most #4/0 THHN |
|---|---|---|
| Electrical metallic tubing | 3.356 | 4 |
| Intermediate metal conduit | 3.630 | 4 |
| Rigid metal conduit (RMC, GRC) | 3.408 | 4 |
| Rigid PVC conduit, Schedule 40 | 3.291 | 4 |
| Rigid PVC conduit, Schedule 80 | 2.874 | 3 |
| Flexible metal conduit (FMC, Greenfield) | 3.269 | 4 |
| Liquidtight flexible metal conduit (LFMC) | 3.246 | 4 |
| Electrical nonmetallic tubing (smurf tube) | 3.291 | 4 |
#4/0 THHN in other Flex sizes
Other wire sizes in 2" Flex
#14: 135#12: 98#10: 62#8: 35#6: 25#4: 16#3: 13#2: 11#1: 8#1/0: 7#2/0: 6#3/0: 5#4/0: 4250 kcmil: 3300 kcmil: 3350 kcmil: 1500 kcmil: 1