NEMA’s electroindustry May 2010 - 11

electrical safety
Plug-In Abbreviations
CCID GFCI EV EVSE PHEV charging circuit interrupting device ground-fault circuit interrupter electric vehicle electric vehicle supply equipment plug-in hybrid electric vehicle EVSE feeders and branch circuits must be sized for continuous duty and have a rating no less than 125 percent of the maximum load of the EVSE. Where non-continuous loads are supplied from the same feeder or branch circuit, the overcurrent device must have a rating no less than the sum of the non-continuous loads plus 125% of the continuous loads. For Level 1 charging, either a 15- or 20-amp single-pole circuit breaker at the beginning of the
Image courtesy of National Renewable Energy Laboratory

The EVSE includes the charge coupler, which is the plug that connects the car to the associated EV-rated cord. The EVSE must provide disconnecting means to remove power from the cord if the cord is experiencing undue stress that could cause a live part to be exposed. The personnel protection system that functions within EVSE equipment is called a charging circuit interrupting device (CCID), which is similar to a standard ground-fault circuit interrupter (GFCI) that is installed in most bathrooms, kitchens, and garages throughout the country. The GFCI is mandated by the National Electrical Code® (NEC). The CCID can be developed with an automatic reclosure after a nuisance trip, allowing the unit to self check and resume charging automatically. Currently, only Level 1 and Level 2 charging equipment are provided for personal use. NEC requires that all components (materials, devices, fittings, etc.) be listed or labeled. Level 1 EVSEs must comply with the following specific code and regulatory requirements: • EVSE can be fastened in place or be cord-and-plug connected, but must not have exposed live parts and must be grounded at all times • EVSE must incorporate a UL recognized SAE J1772 Charge Coupler • All EVSEs must be marked “For Use with Electric Vehicles”

circuit, located in the meter-panel breaker section, will meet this requirement. Note that with a 15to 20-amp circuit breaker, charging at 12 amps will overload the circuit if an additional 4- to 9-amp load is also on the branch. EVSE charging cables must not exceed 25 feet in length without specific cable management, and they cannot have midcord couplings. Cables must be type EV, EVJ, EVE, EVJE, EVT, or EVJT flexible cable. EV charging cables and connectors come with the charger. The connector must include an interlock to de-energize it when it is unplugged from the vehicle, or when

it is subjected to stress that may rupture or break it, or when it becomes a shock hazard. The grounding pole for conductive connectors are the first contact made and last broken. For inductive charging, the EV and EVSE are electrically isolated, which prevents shock hazard. At this time, the NEC has a no “back-feed of electricity to residence” requirement. The EV cannot serve as a standby power supply for the house, and a means must be provided to prevent power from being fed back to the residence. Many years have been invested toward developing EVSEs and their associated safety concerns. The PHEV industry is growing. Safe, reliable, and easy to install EVSE is necessary to ensure that this new industry is successful. ei Kenneth Brown has been involved with developing surge protective devices, power distribution units, and other power-related products for 14 years. He is currently chair of the IEEE Surge Protective Devices Committee, and a member of the UL Standards Technical Panel.

The more the industry can do to reduce cost and complexity [of EVSEs], the more the customer will be satisfied.

NEMA electroindustry

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May 2010

NEMA’s electroindustry May 2010

Table of Contents for the Digital Edition of NEMA’s electroindustry May 2010