How many #3/0 THHN fit in 3" Rigid?
113/0 AWG THHN/THWN-2 wires in 3" Rigid metal conduit (RMC, GRC)
7.499 sq in × 40 % = 2.9996 sq in allowed. ÷ 0.2679 sq in per wire = 11.20, so 11.
This pull in numbers
- 11 wires fill
- 39.3 % of 3" Rigid
- Limit for three or more
- 40 %
- For 12 or more
- 3-1/2" Rigid, up to 15
- Pipe to wire diameter
- 5.29 to 1
- In THW insulation
- 9 fit
- In XHHW-2 insulation
- 11 fit
Before you pull 11
- The ground counts. Every wire in the pipe counts toward fill, the green or bare ground and the neutrals too. 11 is the total, not the hots.
- Derating. If all 11 were current-carrying, each would be adjusted to 50 % of its ampacity (Table 310.15(C)(1)): a #3/0 THHN at 225 A in the 90 °C column becomes 112.5 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.
#3/0 THHN in other 3" conduit
| Conduit | Inside area | Most #3/0 THHN |
|---|---|---|
| Electrical metallic tubing | 8.846 | 13 |
| Intermediate metal conduit | 7.922 | 12 |
| Rigid metal conduit (RMC, GRC) | 7.499 | 11 |
| Rigid PVC conduit, Schedule 40 | 7.268 | 11 |
| Rigid PVC conduit, Schedule 80 | 6.442 | 9 |
| Flexible metal conduit (FMC, Greenfield) | 7.069 | 10 |
| Liquidtight flexible metal conduit (LFMC) | 7.475 | 11 |
#3/0 THHN in other Rigid sizes
Other wire sizes in 3" Rigid
#10: 142#8: 82#6: 59#4: 36#3: 31#2: 26#1: 19#1/0: 16#2/0: 13#3/0: 11#4/0: 9250 kcmil: 7300 kcmil: 6350 kcmil: 5500 kcmil: 4