Type of NEMA plugs used for EV Charging

NEMA is short for the ‘National Electrical Manufacturers Association’ and it governs the many plug types used in domestic alternating current (AC) power supply.  The U.S. has many different plug types used in residential houses, which range from lower power plugs such as NEMA 5-15 and NEMA 6-20, which provide lower amps to more higher powered 50 amps plugs.  NEMA 5-15 and NEMA 60-20 were the standard level 1 chargers that were introduced to the U.S. market when the first electric vehicles were introduced in 2010.

NEMA nomenclature is written as NEMA|5|15|P for example. NEMA is National Electrical Manufacturers Association’, “5” indicates the voltage in this case 125 volt grounded and “15” indicates the current rating.  The current rating measured in amps is often 15, 20, 30 or 50 amps. A NEMA 620P would indicate 250v (6 = 250 volts) and 20 indicates 20 amps.  A NEMA 14-50 indicates 125/250V three phase and 50 amps.  A NEMA 6-50 indicates 250 volts and 50 amps.   The voltage rating provided is the highest voltage allowed for use with an electrical device.

Three phase power is not typically available residentially in the U.S. and is very uncommon.  3 phase supply power is more common in Europe.  

When the first electric vehicles were launched in the U.S., the size of the batteries was very small and they lacked power, which dictates electric driving range.  This meant that fast charge times to charge or “fill” the battery with electricity could be achieved through a level 1 ev charger, even though the power output of  level 1 chargers is generally low.   

The first plug-in hybrid electric vehicles such as the Nissan Leaf, the Chevrolet Volt, the Toyota Prius and the Toyota hybrids had a very small lithium ion battery, typically below 4 kilowatt hour (kWh).  To fully charge an early model electric vehicle it would take around 2 hours.  This is because an ev charger with a NEMA 5-15 plug or NEMA 6-20 plug can produce 2-3 kilowatts of power per hour.  A 4 kWH battery receiving 2 kilowatts of power per hour would be charged in 2 hours (4 kWh battery divided 2 kWh of charge per hour)

As car battery sizes increased and the battery acceptance rates increased also, more powerful charges were needed.  A battery with a 30 kWh battery is 10x the size of a 3 kWh battery and so if your charger is only providing for example 3 kWH of power per hour, then your charge time is 10 hours (30 kWh battery divided by 3 kWh of charge per hour).

Over time, the EV charging industry was able to take advantage of the fact that many U.S. households had more powerful plug capacities in garages, tool sheds and outdoor laundry areas.  NEMA 14-50, NEMA 6-50, NEMA 14-30 and NEMA L14-30 are examples of level 2 chargers.  These plugs are 250 volt plugs and can provide much faster charging.  They were traditionally used for washer, dryers, stoves and heavy machinery. 

NEMA 10-30 and NEMA 10-50 are plug types that we do not sell EV chargers for.   These plug outlets do not have a grounding wire, which is an electrical safety hazard.  We recommend having a licensed electrician replace these plug receptacles with grounded plug receptacles such as NEMA 14-50 or NEMA 6-50.

In terms of watch outs with EV chargers, 3rd party sellers on marketplace exchanges are commonly making two major mistakes:-

1. Selling level 1 and level 2 portable or wall ev chargers with NEMA 10-30 and NEMA 10-50 plug types.  These are no longer code as current national code requires a ground line.  These older outlets are not safe for use to charge an electric vehicle.  These plugs do not have a ground wire and if a neutral is used instead, then this can create an electrical charge on the body of the vehicle, which is a significant safety hazard during or after charging.  A licensed electrician should be used to replace these type receptacles.
2. Supplying level 1 and level 2 ev chargers with circuit boards amps (in the charger) that match the amps of the electrical circuit in your home.  In practice, this means supplying, for example, an ev charger with a 50 amps electrical charge and running it through a 50 amps plug.   50 amps is the level at which a 50 amp breaker is designed to cut off, creating inconvenience when the breaker trips (too much power).  Most industry specialists recommend that you use 80% of the breaker’s capacity. So for a 30 amp breaker, you should be using at a maximum 24 amps. For a 50 amp circuit, you should be using at a maximum 40 amps. Using a dedicated 30 amp or 50 amp breaker, a dedicated outlet and 80% of the breaker’s capacity, ensures you don’t exceed the capacity of the circuit when using the ev charger.

Below is an image and descriptor for the different plug types we offer in our ev charger range.  Level 2 chargers especially should remain plugged in (just like your washer or dryer would be) and not be unplugged or moved about.

NEMA Plug Types used with EV chargers

EV-Chargers™ takes the complex and makes it simple.  We have created a simple drop down menu to help you find the right and the right charge power to match your vehicle and its battery. We provide the widest range of level 1 and level 2 chargers with the most common NEMA plug types all available as portable chargers.