Charging Station Design & Specifications

Close-up of multiple EV charging connector types including J1772, CCS Combo, CHAdeMO, and NACS arranged on a technical workbench with studio lighting

EV Charging Station Design

This lesson covers the technical specifications and design principles for EV charging installations.

Charging Levels

  • Level 1 (120V AC): 1.4–1.9 kW — overnight home charging; minimal infrastructure. Suitable for low-daily-mileage fleet vehicles parked overnight at employee residences.
  • Level 2 (240V AC): 3.3–19.2 kW — workplace, destination, and fleet depot charging. The right choice for most AMPS tribal facility installations.
  • DC Fast Charging (480V+ DC): 50–350+ kW — highway corridors, high-utilization sites, and fleet operations requiring rapid turnaround. Note: Some high-power DCFC systems operate above 480V DC; CCS can exceed 1,000V DC at maximum power levels.

Connector Standards

Technical comparison illustration of four EV charging connector types: J1772, CCS Combo, CHAdeMO, and NACS shown as detailed drawings
The four major EV connector types: J1772 (AC), CCS Combo (DC), CHAdeMO (legacy DC), and SAE J3400/NACS.
  • SAE J1772: Standard Level 1/2 AC connector. All non-Tesla EVs in North America use this for AC charging.
  • CCS Combo (Combined Charging System): Adds DC fast charging pins to the J1772 handle. The dominant DC fast charging standard for most EVs in North America.
  • SAE J3400 / NACS (North American Charging Standard): SAE formally standardized the Tesla connector as J3400 in 2023. Major automakers (Ford, GM, Rivian, Honda, Nissan, and others) have adopted J3400/NACS for 2025+ model years. New EVSE should support both CCS and J3400/NACS via dual-port design or multi-standard connectors.
  • CHAdeMO: Legacy DC fast charging connector, primarily used by Nissan Leaf (older generations) and Mitsubishi. Phasing out in North America — new installations should not prioritize CHAdeMO.
Electrical Safety — NEC 625
NEC Article 625 governs all EVSE installations. Circuits must be sized at 125% of continuous EVSE load (625.22), and GFCI protection is required at outdoor locations and garages (625.54). Non-compliance is a code violation and a safety hazard.
Exploded cutaway view of a Level 2 EV charging station showing all major components: housing, circuit board, power electronics, cable management, and connector
Activity: Identify the major components of a Level 2 EV charging station.

Electrical Design

NEC Article 625 governs EVSE installation requirements. Key design elements:

  • Branch circuit sizing: NEC 625.22 requires circuits sized at 125% of continuous EVSE load
  • GFCI protection: NEC 625.54 requires GFCI at outdoor locations and garages
  • Grounding and bonding: EVSE enclosure and conduit must be properly bonded
  • Load management: Multiple EVSE on a shared service may require dynamic load balancing systems
Future-Proof Your Design
Install conduit that is 25–50% larger than current needs. Adding conductors later is inexpensive; trenching for new conduit is not. Plan for SAE J3400/NACS compatibility — it will be the dominant standard by 2027.

Tribal Land Design Considerations

On Fort Mojave tribal land, additional design factors apply:

  • Shade canopies: Required for equipment protection and user comfort in Mojave temperatures (110°F+ summers).
  • Conduit sizing: Install conduit 25–50% oversized for future capacity additions without trenching.
  • Security: Consider cable anti-theft locks and vandal-resistant enclosures appropriate for tribal community sites.
  • Signage: Tribal language inclusion on EV charging signage supports community adoption.
Charging Level Selection Guide by Use Case

Employee/residential overnight: Level 1 (120V) is sufficient for vehicles driven less than 40 miles/day. Zero infrastructure cost beyond a dedicated outlet.

Tribal facility/workplace: Level 2 (7.2–19.2 kW) is the standard. Vehicles charge in 4–8 hours, perfect for workday or overnight depot use. This is the primary AMPS installation type.

Public highway corridor: DCFC (50–150 kW) for through-traffic. Higher infrastructure cost but necessary for corridor coverage. Requires 3-phase power and significant electrical service.

Fleet rapid turnaround: DCFC (50–350 kW) for vehicles that need midday top-ups between routes. Cost-effective only at high utilization sites.

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