WireGaugeCalc Free calculator · NEC cited · works offline
Ground Wire For 1200 Amp Service
ground wire for 1200 amp service is quick to size with WireGaugeCalc.
The calculator reads the NEC equipment grounding and grounding electrode tables for your conductor material, so you match the gauge to the service rating.
You confirm the right copper or aluminum size before you order the conductor.
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.
Sizing The Grounding Conductor At 1200 Amps
Equipment grounding conductors follow NEC 250.122 and scale with the overcurrent device, so a 1200 amp service lands near 3/0 copper.
Grounding electrode conductors follow NEC 250.66 and have their own ceiling, since the electrode path is sized differently from the bonding path.
WireGaugeCalc separates the two so you do not confuse the equipment ground with the electrode conductor.
Inputs That Drive The Ground Gauge
The calculator asks for the values that set the conductor size:
- Service rating set at 1200 amps
- Conductor material, copper or aluminum
- Equipment ground versus grounding electrode conductor
- Termination temperature column
- Parallel sets if the service uses multiple raceways
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 copper equipment ground does a 1200 amp service need?
NEC 250.122 points to roughly 3/0 copper for a 1200 amp overcurrent device. Verify the exact size against the current NEC and your local authority having jurisdiction before ordering.
Is the grounding electrode conductor the same size?
No, the electrode conductor follows NEC 250.66 and tops out smaller than the equipment ground at large services. The calculator handles each path separately.
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.