Charger savings: Nema 14-50 vs. Tesla HPWC


I received the following question from a Tesla customer:

“After looking into the charger options some more I was wondering how much it would cost if we went with the NEMA 14-50 installation instead, as the [HPWC] wall connector and the NEMA both seem to charge at the same capacity/time?”

I get this question, in one form or another quite regularly. I thought that the answer might be something that I can share on our blog.



Charge rate

The standard equipment charger that comes with the car and plugs into a NEMA 14-50 receptacle also delivers energy at 32 amps. In this case, the customer is correct. Due to the size of her service (100 amps), we’ll be setting her Tesla HPWC (High Powered Wall Connector) for 32 amps.

A standard car is able to receive a charge at the rate of 48 amps. If the customer has a sufficiently large service, it’s always our preference to supply a feed and set the HPWC to the highest charge rate.

If this customer was to buy a HPWC, and at some point in the future upgrade the service, it may be possible for us to upgrade the feed to the HPWC and set it for 48 amps. This would not be possible if they only had the NEMA 14-50 receptacle.


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The standard equipment charger that comes with the car is bundled together in a bag with a J1772 adapter, a 220-volt adapter and an adapter for use in a normal 120-volt household outlet. As a Model S owner, I’m happy to carry all of this together in the car. It gives me some peace of mind to know that I have the option to pull it out and get a bit of a charge.

I also tend to use it when I’m traveling and staying at friends’ or family. If I’m using it daily at home I have to decide in advance if I’m going to need it so I can pack it away.

I really just prefer to have my HPWC at home and the standard unit neatly packed away in my car.


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The heart of the question was, of course, cost. Could she save some money by installing an outlet instead of an HPWC?

The installation takes about the same amount of time and material to do the job with the receptacle or the HPWC, so there wouldn’t be any savings on the install itself. But of course, she wouldn’t need the HPWC. In Canada, the HPWC is about $750.00 plus HST.

At present time, the province of Ontario (where this customer is located) is offering a $1,000 rebate to customers who purchase and install a charger. There are certain conditions that apply to the rebate. You can view the details here.

In short, she would not receive the rebate for installing the receptacle only. If she were to purchase the HPWC, it would essentially be free and she would have a few dollars left over to apply to the install.

That second (or third) car

In mid-2016, Tesla released a new redesigned HPWC.

The new charger was significantly cheaper and featured a “power sharing” function. This feature will be of interest to those that might want a second Tesla car.

Tesla describes the feature on its website:

“Power sharing allows a single circuit breaker to be connected and shared, servicing up to 4 Wall Connectors – an optimized solution for customers with multiple Tesla vehicles.”

For virtually all of the installations that we complete, the service size could not accommodate a second charger. The answer is to use the sharing feature, and use the single feed to share amongst all the cars.

I’m told by Tesla that the sharing feature is dynamic. It doesn’t simply split the feed in two (or three or four) but looks into the cars to see where the greatest charge is needed and attempts to get both cars fully charged overnight.

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Currently, in the Province of Ontario, it makes little sense not to purchase the HPWC. In fact, almost all Signature Electric EV customers opt for this charger option with very few exceptions.

While this answer is very Tesla specific we do have similar options for other EV owners.

If you want some information on your specific need please feel free to contact me at or call us at 416-490-8093.


Mark Marmer