WireGaugeCalc Free calculator · NEC cited · works offline
200 Amp Service Wire Size Copper
200 amp service wire size copper is fast with WireGaugeCalc, since you enter the amps, copper material, and the termination temperature and read the result.
The calculator checks the load against the NEC 310.16 ampacity table so the conductor you pick carries the current without overheating.
You get the copper gauge for the run in seconds, so you can size the service and move on.
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.
Conductor Size for 200 Amp Service
The conductor size for a 200 amp service depends on the copper ampacity at the listed termination temperature, so the calculator uses the 75C column unless your equipment is rated otherwise.
Copper at 75C reaches 200 amps near 3/0 AWG, so the tool flags that as the starting point for a standard service.
It also accounts for the 83% dwelling service rule where it applies, since that can shift the result.
200 Amp Minimum Cable Size on Copper
The calculator returns the 200 amp minimum cable size after you confirm a few inputs:
- Copper conductor material
- 200 amp service rating
- Termination temperature, usually 75C
- Whether the 310.12 dwelling service allowance applies
- Run length, in case voltage drop matters
- Conduit or cable assembly type
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 wire size is needed for a 200 amp service?
At the 75C termination column, 3/0 AWG copper is the common size for a 200 amp service. If the 310.12 dwelling service allowance applies, a smaller copper size may be permitted, so confirm the conditions for your job.
Does the termination temperature change the copper size?
Yes, since the ampacity column you use is set by the lowest-rated termination on the breaker, lug, or device. Using the 60C column instead of 75C can push the required size up, so verify the equipment listing against the current NEC and your local authority having jurisdiction.
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.