WireGaugeCalc Free calculator · NEC cited · works offline
Parallel Conductor Ampacity Calculator
Parallel conductor ampacity calculator is quick with WireGaugeCalc, since you set the size and the number of sets and read the total.
It pulls each conductor's rating from the right termination temperature column and adds the parallel sets together.
So you can confirm the combined ampacity meets your load.
Open the calculatorAllowable ampacity from NEC Table 310.16 at the chosen termination temperature. Field aid only, verify against the current NEC and your local authority having jurisdiction.
Combine Ratings From The Termination Column
You pick the conductor size, material, and termination temperature, and the calculator reads the per-conductor ampacity.
Since parallel sets share the load, it multiplies that rating by the number of conductors per phase.
The 60C, 75C, and 90C columns are built in, so the result matches your equipment terminals.
What Drives Parallel Ampacity
The total depends on each conductor and how many you run:
- Reads ampacity from the 60C, 75C, or 90C column
- Multiplies by the number of parallel sets per phase
- Handles copper and aluminum
- Limits the per-conductor value to the termination rating
- Shows the combined ampacity against your load
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 is the smallest size I can run in parallel?
The NEC generally allows paralleling at 1/0 AWG and larger, with limited exceptions for specific cases. Confirm the size and exceptions against the current NEC and your local authority having jurisdiction.
Do all parallel conductors have to be the same?
Yes, conductors in the same parallel set must match in size, material, length, insulation, and termination method. That keeps current sharing equal across the conductors.
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.