WireGaugeCalc Free calculator · NEC cited · works offline
900 Amp Electrical Wire
900 amp electrical wire sizing is fast with WireGaugeCalc, since you enter 900 amps and the calculator builds the parallel conductor set from the NEC 310.16 ampacity table.
A single conductor cannot carry 900 amps, so the tool splits the load across paralleled sets per NEC 310.10(G).
So you get a workable parallel arrangement instead of an oversized single run that does not exist.
Open the calculatorEnter any two values and read the rest.
Ohm’s law: V = I × R and P = V × I. Field aid only, verify against the current NEC and your local authority having jurisdiction.
How 900 Amps Splits Into Parallel Sets
No standard conductor reaches 900 amps alone, so the load is divided across two or more equal sets run in parallel.
Each set must be the same size, length, and material, since unequal runs share current unevenly and overload one path.
The termination temperature still sets the ampacity column, so the lug rating decides how large each parallel conductor must be.
What You Get For A 900 Amp Feeder
Enter the load and material and the result lays out the set:
- The number of parallel conductors per phase
- Conductor size per set from NEC 310.16
- Copper versus aluminum for each path
- The combined ampacity above the 900 amp load
- A reminder that paralleled runs must match in length
- The termination column used for the sizing
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 wire carries 900 amps?
There is no single conductor for 900 amps, so it is run as parallel sets, such as three sets of 4/0 copper. Confirm the arrangement against the current NEC and your local authority having jurisdiction.
Can I parallel different size conductors for 900 amps?
No. NEC 310.10(G) requires paralleled conductors to be the same size, length, material, and insulation so each path carries an equal share of the load.
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.