WireGaugeCalc Free calculator · NEC cited · works offline
Cable Size 150 Amp Box 150 Ft From Meter
Cable size 150 amp box 150 ft from meter is fast with WireGaugeCalc, since you enter the load, distance, and conductor material and the app returns a code-compliant size.
The calculator starts from NEC 310.16 ampacity for the 150 amp feeder, then checks voltage drop across the 150 foot run so the conductor stays inside the 3% guideline.
You get the copper and aluminum size on one screen, so you can size the feeder to the box without flipping through tables.
Open the calculatorSmallest conductor whose ampacity meets the load, NEC Table 310.16. Field aid only, verify against the current NEC and your local authority having jurisdiction.
Why 150 Feet Changes The Conductor Size
A 150 foot run adds resistance, so the conductor that only meets ampacity may still drop too much voltage at the box.
WireGaugeCalc compares the ampacity size against the voltage drop size and reports the larger of the two.
Since copper and aluminum behave differently over distance, the app shows both so you can pick the material you are installing.
Sizing The Feeder For A 150 Amp Subpanel
The app handles the inputs that decide the feeder size:
- 150 amp load at the box, sized off the NEC 310.16 75C column
- 150 foot one-way run length for the voltage drop check
- Copper or aluminum conductor selection
- Voltage drop held to the 3% branch and feeder guideline
- Termination temperature so the rating matches the lugs
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 copper size feeds a 150 amp box at 150 feet?
1/0 copper meets the 150 amp ampacity at 75C, but the 150 foot run usually pushes you to 2/0 to hold voltage drop near 3%. Always verify the final size against the current NEC and your local authority having jurisdiction.
Can I use aluminum for this feeder?
Yes, aluminum is common for feeders, but it carries less per size, so a 150 amp box at 150 feet often lands around 4/0 aluminum once voltage drop is included.
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.