EV Load Calc: NEC Wire & Fill

EV Load Calc is the electrical load calculator built for electricians, contractors, and engineers who install EV charging equipment. Every calculation references the NEC (NFPA 70) with full transparency - see the exact article, formula, and math behind every result.

Built by a low-voltage integrator who got tired of flipping through the code book on ladders. If you spec, permit, or install EV chargers, this is the tool that lives in your pocket.

⚡ SINGLE CHARGER SIZING

Size a residential EV charger circuit in seconds. Enter the amperage, voltage, run distance, conductor material, and insulation type. Get:

- Circuit breaker size (NEC 240.6(A), 210.20(A))
- Minimum conductor gauge (NEC Table 310.16)
- Voltage drop percentage with pass/fail (NEC 210.19(A))
- Automatic wire upsizing when voltage drop exceeds 3%
- Ambient temperature derating (NEC Table 310.15(B)(1))
- Wire cost estimate with custom $/ft override

🔌 MULTI-CHARGER / FLEET SIZING (PRO)

Size feeder circuits for commercial and fleet installs with 2-20 chargers. Compare results with and without an Energy Management System (EMS) per NEC 625.42 to see how much you save on breaker and conductor sizing.

🏠 PANEL CAPACITY CHECK (PRO)

Find out if an existing residential panel can support an EV charger before you pull a permit.

- NEC 220 Standard Method with full demand factors
- NEC 220.82 Optional Method toggle for comparison
- General lighting, small appliance, laundry, fixed appliances, range, dryer, HVAC, and EV charger loads
- Pass/fail verdict with headroom or over-capacity in amps

📐 CONDUIT FILL CALCULATOR

NEC Chapter 9 conduit fill - select conduit type (EMT, IMC, RMC, PVC, FMC), trade size, and add conductors. Shows fill percentage, pass/fail against Table 1 limits, and recommends minimum conduit size.

🔍 SIDE-BY-SIDE COMPARISON

Compare two charger configurations head-to-head. See which option gives you a smaller breaker, lighter wire, or lower voltage drop - differences highlighted in green.

📋 CHARGER DATABASE

Quick-reference specs for 40+ popular EV chargers from Tesla, ChargePoint, Wallbox, Autel, Siemens, Ford, GM, Rivian, and more. Max amps, voltage, connector type, required breaker, and wire gauge at a glance.

🔢 UNIT CONVERTER

AWG to mm², feet to meters, watts/volts/amps calculator, and kW to amps with 125% continuous load factor.

📄 SHOW YOUR WORK

Every calculation expands to show step-by-step math with NEC article references. Export results as a formatted PDF or share as text - ready for permit applications, AHJ inspections, or client proposals.

💾 SAVE & ORGANIZE

Save calculations with custom names and notes. Pull up past jobs instantly.

🔒 FULLY OFFLINE

No internet required. No data leaves your device. NEC tables are baked into the app for instant results on the job site.

NEC REFERENCES INCLUDED

- Article 625 - Electric Vehicle Charging
- Article 220 - Branch-Circuit, Feeder, and Service Load Calculations
- Article 210 - Branch Circuits
- Article 240 - Overcurrent Protection
- Table 310.16 - Conductor Ampacities
- Table 310.15(B)(1) - Temperature Correction Factors
- Chapter 9 - Conduit Fill Tables
- Article 220.82 - Optional Method

DISCLAIMER

EV Load Calc is an educational and reference tool. It is not a substitute for a licensed electrician or your local Authority Having Jurisdiction (AHJ). Always have a qualified professional review and approve any electrical installation.