WireGaugeCalc Free calculator · NEC cited · works offline
200 Amp Wire Size
200 amp wire size is fast with WireGaugeCalc, since you pick the material and it returns the conductor that meets the load.
The tool reads NEC 310.16 and the termination column you set, so the gauge matches how a 200 amp panel and lug are rated.
You confirm the conductor for a 200 amp service or feeder before you order cable.
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.
What Gauge Wire for 200 Amp Service on Copper and Aluminum
At the 75 degree C column, 2/0 copper carries 175 amps and 250 kcmil reaches 255 amps, so a full 200 amp feeder uses 250 kcmil copper.
Aluminum has lower ampacity, so the size wire for 200 amp service steps up to 300 kcmil at the same column.
Since NEC 310.12 allows reduced conductors for many dwelling services, the tool can also show the lighter option where it applies.
How the 200 Amp Service Wire Size Result Is Built
Enter the service and the wire gauge for 200 amp service answer comes from these inputs:
- Copper or aluminum conductor choice
- 60, 75, or 90 degree C termination column
- NEC 310.16 ampacity at 200 amps
- Dwelling service reduction under NEC 310.12
- Standard AWG and kcmil sizes
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 awg for 200 amp service on a dwelling?
NEC 310.12 allows 4/0 aluminum or 2/0 copper for a 200 amp dwelling service or feeder under the 83 percent rule. A full 200 amp feeder under Table 310.16 needs 250 kcmil copper or 300 kcmil aluminum. Confirm which rule applies with the current NEC and your local authority having jurisdiction.
Why can a 200 amp service use smaller wire than the table shows?
NEC 310.12 lets a main dwelling service carry the load at 83 percent, since the demand on a home rarely sits at the full rating. That reduction allows 4/0 aluminum where a general feeder would need more.
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.