Electric Vehicle Charging
by Jeff Keljik, Director of Education
2017 Tesla Model X- sport utility vehicle with a horsepower of up to 518 hp - all electric. It has a range of 237 to 289 miles by battery power only, and goes zero to 60 mph in 2.9 seconds. It can be yours for as little as $79,500. A 2017 Model 3 goes for a mere $35,000. This is great news for the electrical industry because the electric car batteries need recharging.
Article 625 was put into the NEC in 1996 as a forward thinking article to get ready for the electric vehicles of tomorrow. Tomorrow is here! Article 625 is used for automotive type battery charging, rather than for electric fork lifts and golf cart type vehicles. As many people have seen, the cord connected charging stations are popping up all over. Article 625 in the 2017 NEC has added more definitions and more requirements for charging electric vehicle, including wireless charging of vehicles. Do you know WPT and WPTE mean? Wireless Power Transfer and Wireless Power Transfer Equipment. How about EVSE or PHEV? Electric Vehicle Supply Equipment and Plug-in Hybrid Electric Vehicle. All of these terms are defined in Art 625.2.
Types of charging systems and how they are installed include:
● Level 1 charging is the slowest form of charging with a typical 120V charger and about 12A and 8-12 hours of charging time.
● Level 2 chargers are 240V and up to 40A of OC protection and 4-6 hours of charging time.
● Level 3 charging is not a specified electrical supply standard but may be 480V and up to 400A.
● Brand new is the Tesla supercharger (sometimes referred to as Level 4)
According to the NEC, the charging loads are considered continuous loads and must be supplied from dedicated branch circuits. Table 625.52(B)(1)(b) is used to determine the cubic ft per minute of ventilation that is interlocked with the chargers if the charging equipment is marked “ventilation required.” Part IV of Article 625 is new and introduces the concept of wireless Power transfer equipment for vehicle charging.