As the world transitions to more sustainable energy solutions, the adoption of electric vehicles has surged, leading to a growing demand for EV charging infrastructure. Installing such equipment presents unique challenges, particularly regarding compliance with building and electrical codes. This article follows the journey to install 20 new EV charging stations in an existing parking garage at a commercial building, and the electrical code difficulties encountered along the way.

Initial assessment and planning

The first step of the project was a comprehensive site assessment to determine the electrical system’s capacity and the optimal locations for the charging stations. The existing electrical infrastructure needed to be evaluated to ensure it could handle the additional load. This phase involved:

• Site survey: Identifying suitable locations for the chargers, considering factors such as accessibility, proximity to electrical panels and safety.
• Utility capacity: EV charging equipment consumes a considerable amount of energy, making it imperative to involve the local utility early in the project planning to ensure it has adequate capacity for the planned EV expansion. Even if the utility can satisfy the demand, there may be significant costs to increase capacity at the project site.
• Load calculation: This assesses the building’s current electrical use and determines the capacity available for new EV chargers.

Compliance challenges

As the project progressed, the planning team identified several National Electrical Code challenges. Each  required careful navigation to ensure Code compliance.

1. Load management and distribution

During the site survey, it was identified that the building’s existing 400A, 277/480V, 3-phase electrical service would likely require modification or an upgrade to accommodate the additional demand. The NEC mandates electrical systems be capable of handling the additional load without compromising safety. Section 220.57 of the 2023 NEC provides guidance on the load calculation requirements for EV supply equipment (EVSE). With 20 new EV chargers, each rated at 22 kilowatts, the total continuous load added was 662A.

The team employed a two-part solution: upgrading the existing 277/480V, 3-phase service from 400A to 800A, and installing an energy management system (EMS) to dynamically distribute power among the chargers. This approach mitigated costs and ensured the total load did not exceed the electrical service capacity, complying with Section 220.70.

2. EVSE disconnecting means

The NEC requires various protections related to EV charging equipment. Compliance is crucial to protect people and property from potential hazards. Section 625.43 requires a readily accessible disconnecting means for EVSE rated more than 60A or 150V to ground. The initial location designated for the EVSE disconnecting means was “accessible” but not “readily accessible” as defined in Article 100. The location for the disconnects was changed during the planning stages to meet the requirement.

3. Wiring methods

The choice of wiring methods and materials is critical, especially in a parking garage with many hazards and environmental conditions. The installation specified schedule 40 PVC, which is Code-compliant, cost-­effective and durable in weather-exposed environments. The PVC was to be run along the walls for the supply and control wiring of the wall-mounted charging equipment.

Installation and inspection

With design and plan revisions in place, the electrical contractor’s team moved forward with the project. The electrical service was upgraded and EMS installed, passing inspection ahead of time. Despite unforeseen utility delays in connecting the new service supply, the whole project proceeded ahead of schedule.

As the project neared completion, the contractor called for a final electrical inspection. Even with careful planning, new challenges emerged, requiring adjustments and corrective actions. Three issues were identified during the inspection.

1. Disconnect location 

Although the disconnects were installed in a readily accessible location, they were remote from the EVSE. Section 625.43 requires a plaque on the EVSE denoting the location of the disconnect.

Solution employed: The contractor had plaques made identifying the location of the EVSE disconnecting means, made from durable material to withstand the environment, and installed them on each EV charger.

2. Protection against physical damage

The EVSE and schedule 40 PVC wiring method were mounted on the wall in front of designated parking spaces. Vehicles could potentially damage the PVC or EV equipment. Section 110.27(B) requires guarding electrical equipment to prevent physical damage. Section 352.12(C) prohibits installing PVC where subject to physical damage, except schedule 80 PVC as permitted by Section 352.10(K).

Solution employed: The contractor installed guard rails and bollards to protect the equipment and PVC wiring. There was enough space to install these protections without hindering access to the chargers.

3. Expansion joints

Section/Table 352.44(A) requires accounting for thermal expansion and contraction with expansion fittings. While the installation accounted for thermal expansion and contraction, it did not consider the expansion joints of the parking garage. Section 300.4(H) requires accommodating potential expansion and contraction of the structure.

Solution employed: The contractor installed expansion/deflection fittings at each structural expansion joint throughout the parking garage.

These violations, though relatively minor, affected the project’s bottom line. Additional material costs for guardrails and bollards, hiring a subcontractor to install them and reworking PVC wiring to accommodate expansion fittings increased expenses. The most significant cost was the hit to the contractor’s reputation with the customer and general contractor.

Lessons learned

This case study highlights several key lessons for future EV charging installations:

• Early and detailed planning: Comprehensive planning and load assessments are crucial to identify potential pitfalls early and ensure the existing infrastructure can support the new load.
• Code familiarity: Thorough knowledge of the NEC and local codes is essential. Regular updates to the codes mean staying informed is critical to avoiding compliance issues.
• Collaboration with stakeholders: Effective communication and coordination with utility companies and AHJs can prevent delays and ensure all requirements are met.
• Adaptability: Flexibility to adjust plans and designs in response to identified issues is vital. Quick problem-solving can save time and resources.

Conclusion

The installation of EV charging equipment, while beneficial, is not without challenges, particularly regarding Code compliance. This case study underscores the importance of meticulous planning, thorough understanding of relevant codes and effective stakeholder collaboration. By anticipating and addressing potential pitfalls, future projects can achieve successful, safe and Code-compliant EV charging installations, contributing to a more sustainable future.

Header image: EVlink