EV Charger Load Calculator

Calculate Level 2 EVSE dedicated circuit breaker, 125% continuous conductor size, and service calculation demand per NEC 2026 §120.57 and Article 625.

NEC edition

Inputs

W

Enter the EVSE nameplate wattage

V
qty

Total EVSE outlets on this circuit or service

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⚡ Test your knowledge
NEC Article 220 was renumbered in the 2026 code cycle. What is the new article number?
  • A. Art. 100
  • B. Art. 120
  • C. Art. 200
  • D. Art. 230
💡 NEC 2026 renumbered Article 220 (Branch-Circuit, Feeder, and Service Calculations) to Article 120.
Energy Management Systems were moved from Article 750 to which article in NEC 2026?
  • A. Art. 100
  • B. Art. 125
  • C. Art. 130
  • D. Art. 150
💡 NEC 2026 moved Energy Management Systems from Article 750 to Article 130.
Which NEC standard size overcurrent device comes after 90A?
  • A. 95A
  • B. 100A
  • C. 110A
  • D. 105A
💡 Per NEC §240.6(A), the standard sizes are …90, 100, 110, 125… There is no 95A standard size.

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How it works & the NEC rules behind it

Electric Vehicle Supply Equipment (EVSE / Level 2 EV chargers) are classified as continuous loads under NEC Article 625 because vehicles can charge continuously for 8 to 12 hours overnight.

Two Key Calculation Requirements:

  • 1. Dedicated Branch Circuit Sizing (NEC §625.42 & §210.19): Branch-circuit conductors and overcurrent protective devices (OCPD) must be sized for at least 125% of the EVSE maximum continuous load rating (e.g. 48A charger × 1.25 = 60A circuit breaker with #6 AWG Copper wire).
  • 2. Service / Feeder Load Calculations (NEC 2026 §120.57 vs 2023 §220.57): Under NEC 2026 §120.57, service load calculation uses the EVSE nameplate rating at 100% (with a 7,200 VA default minimum), rather than the outdated 2023 125% rule!
  • Energy Management Systems (EMS — §625.42(B)): Where an automatic load management system is installed to prevent panel overload, the feeder load can be calculated based on the maximum setting allowed by the EMS.

Formulas & equations

Minimum Circuit Breaker Rating = Continuous EVSE Current (Amps) × 1.25 Conductor Ampacity (75°C Table 310.16) ≥ Breaker Rating Service Demand Load (NEC 2026 §120.57) = Nameplate Watts × 1.00 (7,200 VA default if nameplate unknown)

NEC reference table

EV Charger Output Continuous Amps (A) Required Breaker Size (125%) Minimum Conductor (75°C Cu) Service Load (2026 §120.57)
3.8 kW Level 216 Amps20A Breaker#12 AWG Cu7,200 VA
5.8 kW Level 224 Amps30A Breaker#10 AWG Cu7,200 VA
7.7 kW Level 2 (NEMA 14-50)32 Amps40A Breaker#8 AWG Cu7,680 VA
9.6 kW Level 240 Amps50A Breaker#8 AWG (75°C) / #6 Cu9,600 VA
11.5 kW Level 2 (Hardwire)48 Amps60A Breaker#6 AWG Cu (75°C)11,520 VA
19.2 kW Level 2 (Max AC)80 Amps100A Breaker#3 AWG Cu (75°C)19,200 VA

Worked example, step by step

Example Calculation: Sizing Circuit & Service for Tesla Wall Connector (48A)

Scenario: Hardwiring a 48A 240V Level 2 EV charger in a residential garage.

  • Branch Breaker: 48A × 1.25 = 60.0 Amps. Install a 60A 2-Pole Breaker.
  • Conductor: Table 310.16 requires #6 AWG THHN Copper in conduit (rated 65A @ 75°C). (Note: NM-B Romex #6 is limited to 55A in the 60°C column, so conduit with THHN is required for a 60A breaker!).
  • Service Calculation: 48A × 240V = 11,520 VA added to dwelling service load at 100% per NEC 2026 §120.57.

Frequently asked questions

No! Under NEC §334.80, Nonmetallic-Sheathed Cable (NM-B / Romex) must be sized using the 60°C column of Table 310.16. #6 AWG NM-B is only rated for **55 Amperes**, which is insufficient for a 60A breaker. For a 48A charger requiring a 60A breaker, you must install individual **#6 AWG THHN copper conductors in conduit** (rated 65A at 75°C) or MC cable.

Under NEC §210.8(A)(2) and §625.54, GFCI protection is mandatory for all receptacle-connected EVSE (e.g. plug-in NEMA 14-50 outlets). However, for hardwired EV chargers, many jurisdictions do not require an upstream GFCI breaker because the EVSE has built-in personnel protection (CCID5/CCID20) to avoid nuisance tripping.

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