WireGaugeCalc Free calculator · NEC cited · works offline
What Size Cable For 200 Amp Service
What size cable for 200 amp service is simple to settle with WireGaugeCalc.
You enter the service rating, conductor material, and termination temperature, and the calculator returns the conductor size that meets NEC ampacity.
So your feeder and main lugs are matched before the cable ever gets pulled.
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.
Common Conductor Sizes To Size Wire For A 200 Amp Panel
At 75 degrees C, 2/0 copper carries 175 amps and 3/0 copper reaches 200 amps, so 3/0 copper is a common pick.
Aluminum runs larger, since 4/0 aluminum is the usual 200 amp service conductor under the 75 degrees C column.
The calculator confirms the size against your exact material and column.
Inputs That Decide The Service Cable Size
To size wire for a 200 amp panel the calculator weighs:
- Conductor material, copper versus aluminum
- Termination temperature rating at the meter, main, and lugs
- Service entrance versus dwelling feeder allowances
- Long runs where voltage drop nudges the size up
- Insulation type such as XHHW-2 or THWN-2
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
Can I use 4/0 aluminum for a 200 amp service?
Yes, 4/0 aluminum is a common 200 amp service conductor in the 75 degrees C column for dwelling services. Confirm the application and any reduced conductor allowances against the current NEC and your local authority having jurisdiction.
Do I need 3/0 or 4/0 copper for 200 amps?
3/0 copper carries 200 amps at 75 degrees C, so it usually satisfies a 200 amp service. Pull up to 4/0 copper when long runs add voltage drop or local rules require it.
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.