How Many 6 AWG Wires Fit in RMC Conduit?
Complete NEC-compliant fill chart for 6 AWG THHN wires in Rigid Metal Conduit (RMC) conduit. Maximum wire counts for all standard conduit sizes.
Quick Answer
For 6 AWG THHN wires in RMC conduit at 40% fill (3+ wires):
- • 1/2" RMC: 2 wires
- • 3/4" RMC: 4 wires
- • 1" RMC: 6 wires
6 AWG in RMC Conduit Fill Chart
| Conduit Size | Max Wires (40% Fill) | Fill % | Max Wires (Nipple 60%) | Fill % |
|---|---|---|---|---|
| 1/2" | 2 | 32% | 3 | 48% |
| 3/4" | 4 | 37% | 6 | 55% |
| 1" | 6 | 34% | 10 | 57% |
| 1-1/4" | 12 | 40% | 18 | 60% |
| 1-1/2" | 16 | 39% | 24 | 59% |
| 2" | 26 | 39% | 40 | 60% |
| 2-1/2" | 47 | 40% | 71 | 60% |
| 3" | 70 | 40% | 105 | 60% |
| 3-1/2" | 92 | 40% | 138 | 60% |
| 4" | 117 | 40% | 176 | 60% |
Understanding the Fill Chart
According to NEC (National Electrical Code) Chapter 9, Table 1, the maximum conduit fill percentage depends on the number of conductors:
- 1 conductor: 53% fill maximum
- 2 conductors: 31% fill maximum
- 3 or more conductors: 40% fill maximum
- Nipples (24" or less): 60% fill maximum
This chart shows the maximum number of 6 AWG THHN conductors that can fit in each RMC conduit size while maintaining NEC compliance.
Calculation Example
Question: How many 6 AWG THHN wires can fit in 3/4" RMC conduit?
Wire area: 0.0507 sq in per conductor
Conduit internal area: 0.549 sq in
Allowable fill (40%): 0.2196 sq in
Maximum wires: 0.2196 ÷ 0.0507 = 4 wires
Answer: You can fit up to 4 wires of 6 AWG THHN in 3/4" RMC conduit.