1" Flex conduit fill
1" Flexible metal conduit (FMC, Greenfield) has an inside area of 0.817 sq in (1.020 in across). Three or more wires may take 40 % of it: 0.3268 sq in.
- One wire, 53 %
- 0.4330 sq in
- Two wires, 31 %
- 0.2533 sq in
- Three or more, 40 %
- 0.3268 sq in
- Nipple, 60 %
- 0.4902 sq in
- Support
- Every 4.5 ft, 12 in from boxes
How many wires fit in 1" Flex
All wires the same size and type, by Annex C's method. For a mix of sizes, open the calculator.
| Wire size | THHN/THWN-2 | XHHW-2 | THW/THW-2 |
|---|---|---|---|
| 14 AWG | 33 | 23 | 23 |
| 12 AWG | 24 | 18 | 18 |
| 10 AWG | 15 | 13 | 13 |
| 8 AWG | 9 | 7 | 7 |
| 6 AWG | 6 | 5 | 4 |
| 4 AWG | 4 | 4 | 3 |
| 3 AWG | 3 | 3 | 3 |
| 2 AWG | 3 | 3 | 1 |
| 1 AWG | 1 | 1 | 1 |
| 1/0 AWG | 1 | 1 | 1 |
| 2/0 AWG | 1 | 1 | 1 |
| 3/0 AWG | 1 | 1 | 1 |
| 4/0 AWG | 1 | 1 | 1 |
| 250 kcmil | 1 | 1 | 0 |
Other 1" conduit
| Conduit | Inside area | #14 | #12 | #10 | #8 | #6 |
|---|---|---|---|---|---|---|
| Flexible metal conduit (FMC, Greenfield) | 0.817 | 33 | 24 | 15 | 9 | 6 |
| Electrical metallic tubing | 0.864 | 35 | 26 | 16 | 9 | 7 |
| Intermediate metal conduit | 0.959 | 39 | 29 | 18 | 10 | 7 |
| Rigid metal conduit (RMC, GRC) | 0.887 | 36 | 26 | 17 | 9 | 7 |
| Rigid PVC conduit, Schedule 40 | 0.832 | 34 | 25 | 15 | 9 | 6 |
| Rigid PVC conduit, Schedule 80 | 0.688 | 28 | 20 | 13 | 7 | 5 |
| Liquidtight flexible metal conduit (LFMC) | 0.873 | 36 | 26 | 16 | 9 | 7 |
| Electrical nonmetallic tubing (smurf tube) | 0.832 | 34 | 25 | 15 | 9 | 6 |
About Flex
Flex is supported every 4-1/2 ft and within 12 in of each box (348.30). Short whips to equipment have their own exceptions. See strap spacing and the fill rules.