AWG Wire Gauge Chart
NEC Table 314.16(B) conductor volume allowances for electrical box fill calculations.
| AWG Size | Volume (cu.in.) | Volume (mm³) | Max Amps | Common Uses |
|---|---|---|---|---|
| 18 AWG | 1.50 | 24.6 | 7A | Thermostat wiring, Doorbell circuits |
| 16 AWG | 1.75 | 28.7 | 10A | Extension cords, Light fixtures |
| 14 AWG | 2.00 | 32.8 | 15A | 15-amp circuits, Lighting circuits |
| 12 AWG | 2.25 | 36.9 | 20A | 20-amp circuits, Kitchen outlets |
| 10 AWG | 2.50 | 41.0 | 30A | 30-amp circuits, Electric dryers |
| 8 AWG | 3.00 | 49.2 | 40A | 40-amp circuits, Electric ranges |
| 6 AWG | 5.00 | 82.0 | 55A | 55-amp circuits, Sub-panel feeders |
Conductor Volume Details
18 AWG Conductor
18 AWG conductors are typically used for low-voltage applications and control wiring.
Volume Allowance: 1.5 cu.in. (24.6 mm³)
Maximum Ampacity: 7 amps
Applications: Thermostat wiring, Doorbell circuits, Low-voltage controls
16 AWG Conductor
16 AWG conductors are used for light-duty circuits and appliance cords.
Volume Allowance: 1.75 cu.in. (28.7 mm³)
Maximum Ampacity: 10 amps
Applications: Extension cords, Light fixtures, Small appliances
14 AWG Conductor
14 AWG is the minimum size for standard 15-amp household circuits per NEC.
Volume Allowance: 2 cu.in. (32.8 mm³)
Maximum Ampacity: 15 amps
Applications: 15-amp circuits, Lighting circuits, General outlets
12 AWG Conductor
12 AWG conductors are required for 20-amp circuits and kitchen/bathroom outlets.
Volume Allowance: 2.25 cu.in. (36.9 mm³)
Maximum Ampacity: 20 amps
Applications: 20-amp circuits, Kitchen outlets, Bathroom GFCIs, Garage circuits
10 AWG Conductor
10 AWG conductors are used for 30-amp circuits such as dryers and water heaters.
Volume Allowance: 2.5 cu.in. (41 mm³)
Maximum Ampacity: 30 amps
Applications: 30-amp circuits, Electric dryers, Water heaters, AC units
8 AWG Conductor
8 AWG conductors support 40-amp circuits for ranges and large appliances.
Volume Allowance: 3 cu.in. (49.2 mm³)
Maximum Ampacity: 40 amps
Applications: 40-amp circuits, Electric ranges, Large AC units, Hot tubs
6 AWG Conductor
6 AWG conductors are used for 55-amp circuits and sub-panel feeders.
Volume Allowance: 5 cu.in. (82 mm³)
Maximum Ampacity: 55 amps
Applications: 55-amp circuits, Sub-panel feeders, Large appliances, EV chargers
Understanding NEC Table 314.16(B)
NEC Table 314.16(B) specifies the volume allowance required for each conductor based on its AWG (American Wire Gauge) size. This table is essential for calculating electrical box fill to ensure safe installations that meet code requirements.
How to Use the Wire Gauge Chart
When calculating box fill per NEC 314.16, use this chart to determine the volume each conductor will occupy:
- Identify the AWG size of each conductor entering the box
- Look up the corresponding volume allowance in cubic inches
- Multiply by the number of conductors of that size
- Add up all conductor volumes plus device and equipment fill
- Compare total to box volume to verify compliance
Important Notes
- All conductors originating outside the box and terminating or spliced within the box are counted
- Conductors that pass through without splice or termination count as one conductor each
- Equipment grounding conductors are counted based on the largest ground entering the box
- Pigtails originating inside the box do not count toward fill
Related Resources
Use our free box fill calculator to automatically calculate box fill using these volume allowances. For more information about box fill requirements, see our NEC 314.16 complete guide.