Codes and Standards

Welcome to the Nevada Electric Vehicle Accelerator web page dedicated to building codes and automotive industry standards.

Electric Vehicle Supply Equipment (EVSE)

Electric Vehicle Supply Equipment, also known as EVSE, is the term used to describe the hardware and software technology used to recharge the battery pack of an electric vehicle.

Both the connector plug on today’s electric vehicles as well as the EVSE provided by different automotive manufacturers and third party equipment suppliers are subject to standard specifications defined by the Society of Automotive Engineers (SAE) International.

SAE J1772-2009 Level 1 and Level 2 EVSE Specifications

There are two standard “levels” of AC charging specifications, defined by SAE International.  They have been released by the organization as SAE J1772-2009 Level 1 and Level 2.

Both use the same five-pin connector configuration shown below:

The top two pins and the bottom pin equate to the electric power pin configurations used in standard National Electrical Manufacturing Association (NEMA) outlets standards used in residential homes.  The top two pins carry the “hot” and “neutral” power wiring while the bottom pin is a safety ground connection.  SAE J1772 Level 1 EVSE can carry 120 Volts of AC current up to 16 Amps.  SAE J1772 Level 2 EVSE can carry 240 Volts of AC current up to 80 Amps, allowing a battery pack to recharge two to four times faster than Level 1.

The two smaller pins shown on the lower half of the connector are for communications data signals with software “handshaking” protocols defined by the SAE J1772 Level 1 and 2 standard specifications.

The actual SAE J1772 charging circuitry for the electric vehicle battery pack is usually located onboard the vehicle, itself while the electric vehicle supply equipment is just a “smart relay” that tells the electric vehicle charging circuitry how much power it can supply, so that the vehicle circuitry can tune itself to receive the amount of power that is available behind the smart relay.  Once the communication protocol has been concluded between the the vehicle’s onboard charging circuitry and the EVSE, it closes the contacts of the “smart relay” to allow the power to flow through to the vehicle’s battery pack recharging circuitry.  There should be an audible “click” as the contacts on the relay connect or disconnect after the vehicle is finished charging.

National Electrical Code (NEC) and National Electrical Manufacturers Association (NEMA) Standards

Architects, electrical contractors, general contractors, building inspectors and facilities planners must also be concerned about building codes when installing EVSE in publicly accessible areas or in residential homes.  The National Electrical Code (NEC) provides guidelines for their installation, including: wire gauge and conduit specifications, routing to circuit breaker panels, mounting requirements, vehicle barrier considerations and signage.  There are also related considerations in the NEC code when mounting electrical hardware outside during weather conditions.  The EVSE charging circuit should be on a dedicated electrical line so that it is unaffected by other appliances on the same circuit.

The choice of standard hardware defined by the National Electrical Manufacturers Association (NEMA) to meet other codes and standards specifications is also a consideration when installing EVSE.

Appliance load calculations may be necessary when installing EVSE a home residence to make sure that all appliances in a household have enough power to run when the electric vehicle is added to the mix.

NEVA has partnered with the Electric Vehicle Infrastructure Training Program (EVITP) to conduct two workshops for electricians, architects, building inspectors and planners during May 2012 in order to address NEC requirements, one workshop in the northern part of the state and one workshop in the south.  NEVA has also supported EVITP to help train instructors for its workshop program, who are skilled in training electricians within the International Brotherhood of Electrical Workers (IBEW) about NEC considerations for EVSE installations.

DC Quick Charge Competing Standards

Standards for faster charging capability than those defined by SAE J1772-2009 AC Level 1 and Level 2 are being considered by the automotive industry, especially as battery packs on electric vehicles continue to increase in capacity.  There are competing standards based on a power source of 480 VAC, three-phase power that can provide 400 Volts DC with an electrical current delivering 100 Amps or more.  The Society of Automotive Engineers International has been working to define this standard as SAE J1772 DC Level 2  but has not finalized a universal configuration and protocol at this time.

In order to compensate for the lack of an automotive industry DC Quick Charge  standard, several automotive manufacturers have proposed their own, some that are already in the marketplace today.

Tokyo Electric Power Company (TEPCO) ChadeMo Standard

Nissan and Mitsubishi were the first Japanese manufacturers to introduce battery-powered electric vehicle automotive manufaturers to introduce these vehicles into their country and then worldwide.  The Nissan LEAF and Mitsubishi i-series electric cars both use just lithium-ion battery packs to store the electrical power they use to drive their vehicles’ electric motors for a range of 80 to 100 miles before they need to be recharged.

Both companies chose to use a standard DC Quick Charge system and connector protocol defined by the Tokyo Electric Power Company (TEPCO) as ChadeMo.  ChadeMo is loosely translated from the Japanese language as “charging while drinking tea”.  Other Asian manufacturers like KIA Motors have also adopted the ChadeMo standard, for example the 2014 Kia RAY.  In the U.S., Aerovironment and several other EVSE manufacturers are installing ChadeMo charging systems for DC Quick Charge systems on U.S. interstate highway systems.  These include the West Coast Electric Corridor on interstate I-5 from Vancouver, Canada through the western states of Washington, Oregon and California to Tijuana, Mexico.

Other DC Quick Charge routes have been installed along interstate highways in Texas by the Cracker Barrel chain of restaurants, as well as a planned corridor from Chicago to Phoenix by GoE3.com

U.S. and European Combined Charging System (CCS) DC Quick Charge Standard

Rather than adopt the TEPCO Chademo standard from Japan or wait for resolution of an SAE International standard, nine U.S. and European automakers decided to develop their own DC Quick Charge standard that built on the existing J1772j-2009 AC Level 1 and Level 2 standard.  This was accomplished by expanding the connector pin configuration by adding two more large gauge pins and wires to both the male and female connectors that could handle high power and large amounts of DC current.  This de facto industry standard was dubbed the Combined Charging System (CCS) because it allowed automotive manufacturers to integrate AC Level 1 and Level 2, as well as DC Quick Charge within one single connector plug, rather than requiring two separate distinct plugs, like the separate TEPCO ChadeMo and SAE J1772 standards used by both the Nissan LEAF and Mitsubishi i-series.

Tesla Motors Going Its Own EVSE Way

Tesla Model S EVSE charging port

Tesla Motors has chosen not to comply with EVSE standards in the industry, but adopt its own proprietary recharging technology developed in-house, primarily because the company is using much larger battery pack capacity to achieve longer distance travel by its electric vehicles before they need to be recharged.  The Tesla Motors Roadster can travel a maximum range of 240 miles while the new Model S and Model X can achieve a 300-mile range.

Since the introduction of the Tesla Roadster, the company has found strategic locations for its high-power EVSE stations that use its own connectors and protocols.  By skillfully using adaptor modules, cross-country Roadster drivers have also been able to take advantage of campgrounds equipped with NEMA 14-50 outlets used by recreational vehicles as they drive on the interstate highways.  There are approximately 700 of these campgrounds within 35 miles of  interstate highways from New York to Los Angeles.

The new Tesla Model S connector port shown above can be recharged from both AC and DC high-power sources provided by Tesla motors.  A specialized adaptor can also allow the Model S to recharge from SAE J1772 Level 2 EVSE (see related blog about National Clean Energy Summit 5).

Tesla Motors Supercharger EVSE

The Tesla Model S is now using a battery pack with a capacity of 85 kilowatt-housr to achieve a 300-mile range, compared to a Nissan LEAF with a battery capacity of 24 kilowatt-hours that can achieve a range of 80 to 100 miles.  The EVSE power applied to the Model S battery pack must be at the high end of the SAE J1772 Level 2 standard or greater.  Using its own proprietary high-power EVSE, a Tesla Model S owner can recharge this battery pack in about 6 hours.

Recently, the company has announced that it will soon be releasing and installing “supercharger” EVSE stations that can recharge the Model S battery pack with a capacity of 85 kilowatt-hours  in just 45 minutes at strategic locations throughout the country.

For more information about NEVA Codes and Standards workshops, as well as past events, visit the NEVA Wiki site at: