WireGaugeCalc Free calculator · NEC cited · works offline
80 Amp 240V Cable
80 amp 240v cable is fast with WireGaugeCalc, since you enter the load, voltage, and run and it returns the conductor size.
The calculator reads the NEC 75 degree column for an 80 amp circuit, then runs the 240 volt drop math over your distance.
So you size a subpanel or appliance feeder once, with both heat and length covered.
Open the calculatorEnter any two values and read the rest.
Ohm’s law: V = I × R and P = V × I. Field aid only, verify against the current NEC and your local authority having jurisdiction.
How an 80 amp load sets the conductor and the breaker
At 80 amps the 75 degree column points to 4 AWG copper or 2 AWG aluminum for the cable.
Because 240 volts is line-to-line, the calculator uses the full voltage in the drop formula, so longer runs may need an upsize.
It pairs the conductor with the 80 amp breaker so the feeder and protection match.
What the 240V cable result depends on
The tool combines ampacity and distance from these inputs:
- Load set to 80 amps
- Voltage set to 240 volts
- Copper result near 4 AWG
- Aluminum result near 2 AWG
- One-way run length for voltage drop
- The 3% guideline as the upsize trigger
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
What size cable do I need for an 80 amp 240 volt feeder?
4 AWG copper or 2 AWG aluminum covers an 80 amp load in the 75 degree column. Long runs may need the next size up for voltage drop. Verify against the current NEC and your local authority having jurisdiction.
Does the ground or neutral change with an 80 amp feeder?
The equipment grounding conductor is sized from NEC 250.122, not the same as the ungrounded conductors. The calculator focuses on the current-carrying cable, so size the ground separately.
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.