How many 250 kcmil THHN fit in 1" IMC?
1250 kcmil THHN/THWN-2 wires in 1" Intermediate metal conduit
0.959 sq in × 53 % = 0.5083 sq in allowed. ÷ 0.3970 sq in per wire = 1.28.
This pull in numbers
- 1 wires fill
- 41.4 % of 1" IMC
- Limit for one
- 53 %
- For 2 or more
- 2" IMC, up to 3
- Pipe to wire diameter
- 1.55 to 1
- In THW insulation
- 1 fit
- In XHHW-2 insulation
- 1 fit
Before you pull 1
- The ground counts. Every wire in the pipe counts toward fill, the green or bare ground and the neutrals too. 1 is the total, not the hots.
- Bends. A full pipe pulls hard. Keep to 360° of bends between pull points, less for a tight fill.
250 kcmil THHN in other 1" conduit
| Conduit | Inside area | Most 250 kcmil THHN |
|---|---|---|
| Electrical metallic tubing | 0.864 | 1 |
| Intermediate metal conduit | 0.959 | 1 |
| Rigid metal conduit (RMC, GRC) | 0.887 | 1 |
| Rigid PVC conduit, Schedule 40 | 0.832 | 1 |
| Rigid PVC conduit, Schedule 80 | 0.688 | 0 |
| Flexible metal conduit (FMC, Greenfield) | 0.817 | 1 |
| Liquidtight flexible metal conduit (LFMC) | 0.873 | 1 |
| Electrical nonmetallic tubing (smurf tube) | 0.832 | 1 |
250 kcmil THHN in other IMC sizes
Other wire sizes in 1" IMC
#14: 39#12: 29#10: 18#8: 10#6: 7#4: 4#3: 4#2: 3#1: 1#1/0: 1#2/0: 1#3/0: 1#4/0: 1250 kcmil: 1300 kcmil: 1