How many #4/0 THHN fit in 2-1/2" EMT?
74/0 AWG THHN/THWN-2 wires in 2-1/2" Electrical metallic tubing
5.858 sq in × 40 % = 2.3432 sq in allowed. ÷ 0.3237 sq in per wire = 7.24, so 7.
This pull in numbers
- 7 wires fill
- 38.7 % of 2-1/2" EMT
- Limit for three or more
- 40 %
- For 8 or more
- 3" EMT, up to 11
- Pipe to wire diameter
- 4.25 to 1
- In THW insulation
- 6 fit
- In XHHW-2 insulation
- 7 fit
Before you pull 7
- The ground counts. Every wire in the pipe counts toward fill, the green or bare ground and the neutrals too. 7 is the total, not the hots.
- Derating. If all 7 were current-carrying, each would be adjusted to 70 % of its ampacity (Table 310.15(C)(1)): a #4/0 THHN at 260 A in the 90 °C column becomes 182 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 2-1/2" conduit
| Conduit | Inside area | Most #4/0 THHN |
|---|---|---|
| Electrical metallic tubing | 5.858 | 7 |
| Intermediate metal conduit | 5.135 | 6 |
| Rigid metal conduit (RMC, GRC) | 4.866 | 6 |
| Rigid PVC conduit, Schedule 40 | 4.695 | 6 |
| Rigid PVC conduit, Schedule 80 | 4.119 | 5 |
| Flexible metal conduit (FMC, Greenfield) | 4.909 | 6 |
| Liquidtight flexible metal conduit (LFMC) | 4.881 | 6 |
#4/0 THHN in other EMT sizes
Other wire sizes in 2-1/2" EMT
#12: 176#10: 111#8: 64#6: 46#4: 28#3: 24#2: 20#1: 15#1/0: 12#2/0: 10#3/0: 8#4/0: 7250 kcmil: 6300 kcmil: 5350 kcmil: 4500 kcmil: 3