WireGaugeCalc Free calculator · NEC cited · works offline
10 Gauge Cable Length Limits
10 gauge cable length limits are fast to check with WireGaugeCalc, since the calculator works the maximum run from your load, voltage, and conductor material.
You enter the amps, the system voltage, and copper or aluminum, so the tool returns the length where voltage drop crosses the 3% guideline.
That single number tells you how far you can pull 10 AWG before the run is too long.
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.
Why The Length Limit On 10 AWG Comes Down To Voltage Drop
A 10 AWG copper conductor has a fixed resistance per foot, so a longer run drops more voltage as current flows through it.
Most installers cap branch-circuit voltage drop near 3 percent, and that target sets the practical length limit for the cable.
The calculator solves the run length at that 3 percent point so you size the circuit before pulling wire.
What Sets The Maximum Run For A 10 Gauge Conductor
A few inputs decide how far 10 AWG can go:
- Load in amps, since more current raises the drop
- System voltage, as 240V tolerates a longer run than 120V
- Copper or aluminum, because aluminum has higher resistance
- The voltage-drop target you choose, usually 3 percent
- One-way distance from the panel to the load
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 long can a 10 gauge wire run on a 20 amp circuit?
At 20 amps on 120V copper, a 10 AWG run stays under 3 percent drop for roughly 75 feet one way. Enter your exact amps and voltage to get the number for your job, and confirm the result against the current NEC and your local authority having jurisdiction.
Does the 10 gauge length limit change for 240 volts?
Yes, since voltage drop is a percentage of the supply voltage, a 240V circuit allows about double the run of a 120V circuit at the same load.
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.