WireGaugeCalc Free calculator · NEC cited · works offline
Nec Load Commercail Calculation
nec load commercail calculation is simple with WireGaugeCalc, since you enter the building loads and the app applies the Article 220 factors.
It sums general lighting, receptacle, and continuous loads, then adds the 125% factor for continuous loads as the code requires.
You get a service VA and amp total so you can size the service and feeders.
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.
Building The Nec Commercial Load Calculation
An nec commercial load calculation starts with the unit lighting load per square foot, since Article 220 sets a minimum for the occupancy type.
Receptacle and continuous loads are added, and continuous loads count at 125%, so the service total reflects real demand.
The totals convert to amps at the service voltage for sizing.
What Goes Into The Nec Load Commercial Calculation
A commercial total is assembled from these pieces:
- General lighting at VA per square foot for the occupancy
- Receptacle load, often 180 VA per outlet
- Continuous loads counted at 125%
- Largest motor at 125% of its FLA
- Demand factors where Article 220 permits them
- Convert total VA to amps at the service voltage
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 all loads in a commercial calculation get the 125% factor?
No, the 125% factor applies to continuous loads and the largest motor. Noncontinuous loads count at 100%. Confirm which loads are continuous against the current NEC and your local authority having jurisdiction.
Where do the lighting VA-per-square-foot numbers come from?
They come from the general lighting table in Article 220 for the occupancy type, such as office or store. Multiply that figure by the floor area to get the lighting 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.