NEMA 240 volt outlets come in the following amperage ratings

• 15amps (NEMA 6-15)
• 20amps (NEMA 6-20)
• 30amps (NEMA 14-30)
• 50amps (NEMA 14-50 or NEMA 6-50r)

For most cars they will require a separate adapter to be purchased to work with the corresponding NEMA outlet.

NEMA 14-50 vs NEMA 6-50r – The 14-50 is a 4wire outlet (2 hots, 1 neutral, 1 ground), the 6-50r is a 3wire outlet (2 hots, 1 ground).  14-50 outlets are much more common then 6-50’s, but either one will work!

NEMA outlet pros

• Decent range of charging sizes, from 15 to 50 amps.
• All cars will charge using a NEMA outlet, it does not matter what brand car.
• Overall cheaper to install than purchasing an expensive wall charger

NEMA outlet cons

• Less amperage / charging rate options. Most wall chargers will have increments in 5-10 amps, going up to 60 amps and sometimes above.
• Slower charging speed when comparing a NEMA 14-50 to a wall charger at 60 amps (this is a common comparison)
• Requires a GFCI breaker, box, NEMA outlet, and cover to install leading to a higher material installation cost.  (See below for a clarification on this)
• You will likely need to buy an adapter to charge your car.
• These outlets rely on a pressure connection.  The adapter you have for your car will plug into the NEMA outlet.  If you are constantly plugging in and unplugging your adapter, the outlet will wear out.  Tesla recommends leaving the adapter plugged in all the time for this reason.

Clarification: Yes, it may seem like I contradicted myself here.  If you are providing the wall charger, the installation of it will be cheaper than a NEMA outlet.  This is because of the additional electrical material needed to install the NEMA outlet.  However, when adding in the cost of the wall charger, plus electrical installation, the NEMA outlet will be cheaper.  Take a look at the following cost chart to help clarify this even further as it comes up at most estimate appointments.

As you can see above, the NEMA outlet installation requires these additional materials, a 4wire cable (instead of 3wire), NEMA outlet, box, cover, GFCI breaker (instead of standard) and adapter. The labor for the installation of the two options is the same, the only difference is material cost.  These differences can lead to a material cost increase of $200 or more depending on the length of the wire run. Then add the cost of the adapter ($40-$75) for the NEMA outlet you will need to buy for the car to connect.  If we use a total cost of $250, this is still far less than a Tesla wall charger at $500 + tax/shipping and a ChargePoint home flex at $700 + tax / shipping.

Hard Wired Wall Charger

Hard wired chargers such as the Tesla wall connector and ChargePoint home flex can be used in various amperages and charge rates, from 15 to 60 amp and sometimes above.  

Hard wired charger pros

• Better overall connection to the car
• Large range of amperage / charge speed options
• Cheaper electrical install (if you provide the charger)

Hard wired charger cons

• More expensive overall installation including charger cost
• If you select a Tesla wall connector, it will only charge Tesla cars (their may be an adapter available for this purpose)
• If you move and want to take the charger with you, you will need an electrician to disconnect it.

Plug in Wall Charger

The final kind of installation is a combination of the two above installations.  This means you are purchasing a wall charger (such as the ChargePoint home flex plug in) that requires a NEMA outlet to connect to.

Plug in wall charger pros:

• If you move, you can unplug your charger and take with you!

Plug in wall charger cons:

• The most expensive! You need everything required for the NEMA outlet installation plus the cost of the wall charger itself.
• Slower charging speed when comparing the 50amp NEMA 14-50 to a 60amp hard wired connection
• 1 Extra connection point (the charger plugs in!) that could break down over time.

My Opinion

I am a huge fan of the hard-wired chargers for most scenarios.  They have a better connection to the car and a high range of charge rates to choose from.  I would not get a plug-in charger UNLESS you planned on moving soon and want to take the charger with you without paying an electrician to disconnect it.

I would only choose a NEMA option if your budget is tight as it will be the cheapest overall installation option.

A better question that comes up quite often is whether to get a Tesla charger or other brand? If you feel as though you will stick with Tesla cars long term, their chargers are top notch. They are also cheaper than the ChargePoint home flex units.  IF you do not think you will be sticking with a Tesla long term, get a different brand so you have the flexibility down the road.

How About a FREE Wall Charger?

Check with your town / electricity supplier! Some towns such as Marblehead, MA GIVE away a ChargePoint charger to residents.  This is a great incentive!  The only downside to this is they control the charge speed and will slow it down during peak electricity usage times. Pretty much every Marblehead customer of ours as went with their free charger.  I have not heard any complaints!

Need more help deciding? Contact our electricians today!