Plugged In: What You Need to Know About Installing an EV Charger

As electric vehicles (EVs) become more mainstream, the demand for reliable and fast EV charger installations is growing—both in residential and commercial settings. Installing an EV charger isn’t just about running a wire; it requires careful planning, code compliance, and consideration of future needs.

This article walks you through the essentials of installing an EV charging station, including types of chargers, electrical requirements, NEC compliance, and common design considerations.

Types of EV Chargers

EV chargers are typically classified into three levels:

• Level 1: 120V, used in residential settings with a standard outlet. Provides about 2–5 miles of range per hour.

• Level 2: 240V, used in residential or commercial installations. Provides about 10–60 miles of range per hour.

• Level 3: 480V+ DC fast chargers, used in commercial, fleet, and public settings. Can charge to 80% in around 30 minutes.

Most home and workplace installations use Level 2 chargers for the best balance of speed and cost.

Key Electrical Requirements

1. Dedicated Circuit

   • Each EV charger must be supplied by a dedicated branch circuit.

   • Breaker and conductor size must match the charger's nameplate rating.

   • For continuous loads, multiply the charger's current rating by 125% per NEC 210.19(A)(1).

2. Conductor Sizing

   • Use NEC 310.16 to determine conductor size based on current and insulation type.

   • Copper is preferred; aluminum may be used with proper adjustments.

3. Overcurrent Protection

   • Breakers must not exceed 125% of the charger's continuous load unless otherwise specified.

   • GFCI protection is required in garages and outdoor spaces under NEC 210.8.

4. Wiring Methods

   • Chargers can be hardwired or plug-in.

   • Raceways, conduit, or direct burial cables may be required depending on installation conditions.

Residential Installation Example

• Charger: 40A Level 2

• Breaker: 50A two-pole (40A x 1.25 = 50A)

• Wiring: #6 AWG copper THHN in ¾″ conduit

• Panel: Must accommodate a new 50A breaker

• Distance: Consider voltage drop for long runs between panel and charger

Commercial Considerations

• Multiple EV chargers may require a load management system.

• Consider demand response, networked EVSE stations, and remote monitoring features.

• Public installations must meet ADA accessibility and signage requirements.

• May require service upgrades, larger panels, or new transformers.

Permitting & Inspections

In most cities (e.g., Boise, Nampa, Caldwell), an electrical permit is required. Local requirements generally include:

• Load calculations and panel capacity verification

• GFCI protection for outdoor areas (NEC 210.8)

• NEC-compliant grounding and conduit

• Final inspection before energizing the charger

Visit your city’s building department website to apply for permits and schedule inspections.

Common Pitfalls to Avoid

• Using undersized breakers or wiring

• Ignoring continuous load requirements

• Failing to pull permits

• Not planning for future expansion

• Poor connectivity for smart chargers (Wi-Fi/cellular)

Best Practices

• Use UL-listed EVSE equipment

• Install load management when supporting multiple chargers

• Plan for future demand with larger conduit or panel capacity

• Follow manufacturer instructions precisely

• Always pull permits and ensure inspection compliance

Conclusion

Installing an EV charger—whether at home or for a business—is a smart move toward a sustainable future. But doing it right means more than plugging in. With attention to NEC rules, proper electrical sizing, and local permit requirements, you can ensure a safe, reliable, and future-ready installation.

References

• NEC 2023:

  • Article 210 – Branch Circuits

  • Article 220 – Load Calculations

  • Article 625 – Electric Vehicle Power Transfer Systems

• UL 2202 & UL 2231 – Safety Standards for EV Charging Equipment

• Idaho Division of Building Safety

• City Permit Departments – Boise, Nampa, Caldwell

Disclaimer:
The information, tools, and resources provided on this website are for general informational purposes only. While Empower Engineering strives to ensure accuracy and relevance, no guarantee is made regarding the completeness or applicability of the content to specific projects. Users are responsible for verifying all calculations, code interpretations, and design decisions with licensed professionals and local authorities. Empower Engineering assumes no liability for any loss, damage, or code violation resulting from the use of this website’s content.

Empower Engineering | July 15, 2025