WireGaugeCalc Free calculator · NEC cited · works offline
Conduit For Solar Cable
Conduit for solar cable is quick with WireGaugeCalc, since you enter the PV conductor count and size to see the smallest trade size that fits.
It applies the Chapter 9 fill tables, so the conduit stays at or under the 40 percent limit for three or more conductors.
You get the right EMT, PVC, or RMC size in seconds, so the PV run pulls clean and stays code compliant.
Open the calculatorFill against NEC Chapter 9, Table 1 (40% for 3+ conductors) with Table 4 and Table 5 areas. Field aid only, verify against the current NEC and your local authority having jurisdiction.
Solar conductor count against the 40 percent fill limit
PV strings add up fast, so the calculator totals each conductor area and compares it to the usable area of the conduit.
Since three or more conductors cap fill at 40 percent, the tool sizes the raceway to leave room for heat and pulling.
It handles EMT, PVC, and RMC, so you can match the method used on the array or the inverter feeder.
What the PV conduit fill check needs
Give the tool the run details and it returns a trade size:
- Number of current-carrying PV conductors in the conduit
- Conductor size and insulation type for each set
- Conduit type, EMT, PVC, or RMC
- Equipment grounding conductor counted in the area
- Smallest trade size that stays at or under 40 percent
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
Do I count the grounding conductor in solar conduit fill?
Yes, every conductor in the raceway counts toward the fill area, including the equipment grounding conductor. The calculator adds each one before comparing to the 40 percent limit.
Does rooftop heat change the conduit I should pick?
Rooftop conduit can see high ambient temperatures, which affects ampacity rather than the fill percentage itself. Check both the fill result and the temperature derating 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.