WireGaugeCalc Free calculator · NEC cited · works offline
Cubic Inches Per 14-2 Connection In J-Box
Cubic inches per 14-2 connection in j-box is fast with WireGaugeCalc, since you count the conductors, devices, and clamps and it totals the required volume.
The tool uses the per-conductor allowances in NEC 314.16(B), so each 14 AWG wire adds 2.00 cubic inches.
You learn whether your junction box has the room before you make up the splices.
Open the calculatorConductor volume per NEC 314.16(B). Add device, clamp, and ground allowances for the final count. Field aid only, verify against the current NEC and your local authority having jurisdiction.
How NEC 314.16(B) Counts Each 14-2 Connection
Each current-carrying 14 AWG conductor counts as 2.00 cubic inches under the box fill rule.
All the equipment grounds together count as one conductor, so a 14-2 with ground adds three counted conductors per cable.
Internal clamps and devices add their own allowances on top of the conductors.
Adding Up Volume In A Junction Box
The calculator tallies every item that takes space in the box:
- Count the hot and neutral of each 14-2 at 2.00 cubic inches each.
- Add one 2.00 cubic inch allowance for all grounds combined.
- Add for internal cable clamps if present.
- Add device allowances at double the largest conductor.
- Compare the total to the marked box volume.
One app for every NEC calculation
WireGaugeCalc keeps the calculations you reach for most in one place:
- Voltage drop and wire sizing for any run
- Conduit fill for EMT, PVC, and RMC
- Box fill and junction box sizing
- Ampacity and temperature derating
- Motor circuit and load calculations
- Conduit bend offsets and saddles
Built for the field, works offline
The whole app runs on your phone, so it keeps working in a basement, an attic, or a job site with no signal.
There is no account to create and nothing to load. Open it, run the number, and get back to work.
- No signup and no signal needed
- Answers in a tap, not a spreadsheet
- Same tool on phone, tablet, and desktop
Every result cites the NEC article
Each answer shows the table or formula it came from, so you can check the method and learn the code as you go.
That makes the app useful on the job and during exam prep, since the reasoning is right next to the number.
Switch the code year your job runs on
Jurisdictions adopt the NEC at different times, so you can match the calculation to the code in force:
- NEC 2017, 2020, and 2023 tables
- Copper and aluminum conductors
- 60, 75, and 90 degree C terminations
- Single-phase and three-phase systems
Run the number, then get back to work
Stop flipping through a paper book or hopping between calculator sites. Enter your values, read the code-cited answer, and move on. Free to use, no signup.
Open the calculatorFrequently asked questions
How many cubic inches does one 14-2 cable use in a j-box?
A 14-2 with ground counts the hot at 2.00, the neutral at 2.00, and the ground as part of the single 2.00 ground allowance. The exact total depends on how many cables share the ground count, so verify against the current NEC 314.16(B) and your local authority having jurisdiction.
Do wire connectors or wire nuts add to box fill?
No, wire connectors and pigtails are not counted in box fill volume. Only conductors, clamps, support fittings, and devices are counted.
Is WireGaugeCalc free to use?
Yes. Every calculator is free to run with no signup. A paid tier adds saved projects, PDF reports, and extra code years, but the core math stays free.
Does it work without internet?
Yes. The app runs on your device, so it keeps working with no signal on a job site, in a basement, or in an attic.
Are the results code accurate?
Results follow published NEC tables and standard formulas, and each answer shows the article it came from. It is a field aid, not a stamp of approval, so verify against the current code and your local authority before you wire anything.
Which NEC code year does it use?
You can switch between NEC 2017, 2020, and 2023, since jurisdictions adopt the code at different times. Pick the year your job runs on.