A Comparative Study of KEC and NEC Code for Enhancing EVSE Safety

With the rapid global expansion of electric vehicles (EVs), ensuring the electrical safety and reliability of high-power EV charging infrastructure has become a critical issue. EV supply equipment (EVSE) operates under continuous high-voltage and high-current conditions, increasing the risk of thermal overload, arc flash, and ground faults—major causes of electrical fires. In response, many countries have established their own technical standards tailored to national contexts, while IEC 61851 serves as an international reference for the overall structure and modes of EV charging systems. The United States’ NEC Article 625 presents a quantitative framework for safe EVSE installation, incorporating requirements such as continuous load application, mandatory GFCI protection, and dedicated circuit designs. In contrast, Korea’s KEC 241.17 relies on load diversity factors, simplified protective device criteria, and lacks provisions for arc-flash hazard mitigation—raising concerns over its adequacy in supporting high-capacity fast charging environments. This study conducts a comparative analysis by applying both NEC and KEC Code to a model system composed of two 200 kW DC fast chargers and seven 7 kW AC slow chargers. The comparison focuses on load calculation, overcurrent protection sizing, fire prevention strategies, and circuit configuration. Through this evaluation, the study proposes technical recommendations for improving KEC in alignment with international best practices, with an emphasis on enhancing design, construction, and maintenance standards for EV charging infrastructure in Korea.