Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.

Building new house with EV charging outlet in the garage


2021 MYLR VIN 88,XXX, Rd/Wh, 12/20 delivery
Supporting Member
Oct 28, 2020
Fort Worth
Assume nothing. Confirm the builder is using a commercial grade NEMA 14-50, NOT a $15 outlet from HD or Lowes. There is a difference in the quality and density of the insulating plastic/rubber. Any EV draws a lot of power over a much longer period of time than a household clothes dryer.

Also, confirm the proper gauge wire run from the house breaker box to the NEMA 14-50. Someone else here can chime in and give you those numbers...
Ok. New house, new car.
You can get 32A of 240 VAC charging with a NEMA 14-50 and the Mobile Connector that comes with the car. Call this method 1.
With a Tesla Wall Connector and a 60 amp circuit, you can get 48A of 240 VAC charging. Call this method 2.
Advantage of #1: Cheap, both because even a super heavy duty 14-50 doesn’t cost much and you’ve got the mobile connector anyway.
Disadvantages of #1: No matter how good a 14-50 you get, it’ll wear out eventually. Design use case for such a beast is for a clothes drier or stove, anyway. Wear out won’t be fast, but, still. Next, if you’re using the socket all the time you’ll be hauling the MC out of and into the trunk all the time, a minor pain, along with the possibility of leaving it there in the garage on the day you discover you need it on the road. A spare (a) costs a couple of hundred and (b) has to be stored somewhere.
Slower charge rate: 30 miles per hour or so.
Advantages of #2: Higher charge rate, 45 miles per hour. Infinite (well, not really, but may as well be) number of uses before wear-out. Hangs on a wall and cable storage is wrapped around the body, so, convenient. Mine’s between the two cars at the entry to the garage, so both Teslas get easy access. (Long, 18’ cable’s a good idea.)
The MC stays in the trunk, where $DIETY intended.
Disadvantage: Costs $500 for the box. Normally I’d also mention installation costs, but you’ve got new construction, so an electrician is going to be wandering around anyway.
Wall Connector is kinda specific to Teslas. But I suppose if one is going to take the hike to a CCS one of these days one could future-proof the setup with some box that has both CCS and Tesla connectors, but that’ll be $$$. The Tesla WC is actually cheap for the level of current.
New construction? For $DIETY’s sake, put solar on the roof and make your electricity free. You can get that for less than $20k these days. With incentives and the right state, payback can be as short as 3 to five years; without those, more like 8. But as part of the mortgage, you’d be cash-flow positive from day one.
Your call.


Active Member
Apr 10, 2014
Belleville IL
We had a 50 amp circuit installed with a NEMA 14-50 plug (Romex 6/3, wish I had gone with 4/3 but too late now). Originally I was using a Clipper Creek HSC-50P corded EVSE but after selling our Volt I opted to buy a new Gen 3 WC and add an appliance cord to it so I could retain the 14-50 plug should the WC crap out.

I will update the outlet as the one they installed looks generic. But since I don't plug and unplug the WC I'm not stressing it.

My cost during construction was $300


Well-Known Member
Oct 2, 2020
I put a 100amp SUB Panel in the garage , with extra 50amp breaker. 1 6-50 for welder, I plan to share with charger at night.
The high amperage receptacles such as 14-50, 6-50 typically found in the home are not designed for frequent plugging and unplugging The plug connection will loosen. There are special receptacles for high use applications such as RV parks.


Well-Known Member
Oct 2, 2020
Doesn't 5 LED's illuminated mean the charger is turning out 48 AMPS through a 14-50?
5 LED lights on what unit?

The maximum amperage when charging an EV using a 50A circuit is 80% of 50A (40A.) Charging at 48A requires a 60A circuit, the 14-50 receptacle is only rated for up to 50A and should not be used with a 60A circuit as this could start a fire.
Be forewarned that even if never unplugged, cheap 50A sockets have been known to melt. Search online for "Leviton melt" and you'll find a number of stories. Cheap outlets can have poor wire clamps or may have poor connection with the plug.

I recommended limiting charging speed in the app unless you need the speed. Even though I have a good quality setup, I still limit my own charging to 20A.
  • Like
Reactions: Ormond
New construction, I'd run a 100A subpanel to the garage. That will give you huge flexibility to adapt to pretty much all future needs including non-automotive uses of your garage space. Cheap to do with the walls open.

At the very least run oversize conduit and leave a pull string behind to allow you to run bigger wires easily when they become needed.
What do I need so I can charge a Tesla Model Y?

On Tesla’s website, I see Wall Charger and NEMA 14-50, would either of these work? Do I just plug it in the outlet and will charge Tesla?

Edit: The builder builds houses with these EV charging outlets included so I assume they are 240V
As others have written, assume nothing! Our new home was constructed in 1978 and a 100 amp electrical panel was standard. I opted for a 200 amp panel and paid extra for it. Builders and sub contractors use the cheapest materials they can find. The original Federal Pacific 200 Amp panel had to be replaced as you can no longer sell a house here in NJ that has one due to breaker failures and fires.
Having a main 200 Amp electrical panel in the basement has advantages if any additional circuits are needed after you move in.
Having a 100 amp sub panel located in your garage for EV charging is cheaper to install while your new home is under construction.
FWIW go for the gen 3 HPWC in your garage. I feel the $550 is a better option than a 14-50 outlet.
I decided to go with a Tesla recommended electrician that not only works locally but knows what the electrical inspector is looking for.
Going cheap with charging at 48 Amps is not something that appealed to me. There are numerous electrical fires in the news lately and I certainly do not wish my home to become one of them. I like to sleep at night and not have to worry when I finally receive my Y and its charging in my garage all night.
Just adding on to what @howardnj said. I, too, got bit by the Federated breaker panel problem: The reason that you'll never find a Federated any more is that the breakers wouldn't pop when they were supposed to. I'm not sure, but I'm figuring that the lawsuits over burned-down buildings probably put them out of business. Hence, if one has one of those panels in a house, one can't sell the house until that thing is gone, gone, gone. The neighbor electrician who was doing the house wiring for a kitchen reno spotted it, and out it went. (Kind of fun watching this Master Electrician remove the breakers from the panel before panel replacement. Every time he pulled one of the breakers out, he'd turn to one side and put his other arm across his face and eyes. After watching him do a couple like this, it occurred to me that, if he was doing that, I'd better be doing that as well. Highly likely he knew more about Federated breakers than I did.)
As I said before: the NEMA14-50 (or some other NEMA connector) can certainly charge your car and, even if you get a high-quality NEMA connector, it's got a lifetime associated with how many times one plugs a connector into it. Further, just so it's absolutely, positively, clear:
If you have a socket rated for 50A, then it has to have a breaker rated at 50A, and a wire gauge that, given length of the wire (longer wire for a given current requires a bigger gauge to keep the voltage drop under control), that is also rated at 50A. Not Doing Those Things Means Risk of Fire.
Finally, standard says: If you've got a setup like that, National Electrical Code says max current is 80% of the rating for breaker, wire, and socket.
So, a NEMA14-50 is a 50A socket; 50A breaker; 50A wire, and max load current is not supposed to be more than 50*0.8 = 40A. Period.
But, it gets trickier! Turns out that the National Electric Code has an exception for the breaker/wire/connector of a NEMA14-50: They state that one can run a 40A circuit (that is, breaker, wire, but not connector) with a NEMA14-50. This was put in so that electricians wiring up a 32A load of a clothes drier could cheap out on the wire and breaker.
The problem for Tesla was, they will sell you a NEMA14-50 adapter for the Mobile Connector. But they have zero idea whether the breaker/wire backing up the socket is rated for 40A or 50A. In the interests of safety, then, they assume 40A, and this is the main reason that a Tesla Mobile Connector with a NEMA14-50 won't charge the car any faster than 32A (40A * 0.8).
Now, one can get a Tesla Wall Connector with a NEMA14-50 plug on it. (Or a wall connector from a different vendor, same idea.) And, with that setup, since, presumably, the house owner knows what he/she is doing, one can set the switches/configuration to do 40A (50*0.8). Which is the most that it's safe to do with a NEMA14-50; more than that, and one risks catching the socket on fire.
But! With new construction, or a new circuit (assuming that one doesn't have a 220 outlet in the garage in the first place), why not spend a few more bucks and hard-wire the TWC (or equivalent from some other vendor) to a 60A breaker and wire? In that case, one will be able to charge at the maximum rate that most Teslas can do: 48A at 220.
Last comment. Most Teslas sold these days (Model 3, Model Y, Performance and Long Range) have three 16A AC to DC converters in them, allowing for 48A of charging current at 220. But there are Teslas out there, like the Standard Range ones that have, like, 270 miles max range, that only have two of those 16A AC to DC converters; max charge current on those guys is 32A. That changes the equation a bit: The convenience of the TWC is undeniable, but the fact that the car won't allow for a faster charge rate than 32A changes the equation a bit.

Final note. Lots of people do their own house wiring. I do repairs and odd jobs like that from time to time. I have enough experience at this kind of thing that that Master Electrician had no qualms using me as an Electrician's helper, albeit a dumb, inexperienced one. Heck, I even added a utility-grade electric power meter to my solar panel system and had it inspected by the town inspector with no problems.
But I know where my limits are. When one puts electrical cable in a wall: There's a difference between what cable gets used in ducts, in walls, and whether it's vertical or not. Electricians adding circuits to breaker panels sweat what the maximum load is; they have Equations. And knowledge. The National Electric Code is hundreds of pages; as a Civil Engineer told me one day, every page in such a code is How To Do It so the House Doesn't Burn Down.
So, when getting the Tesla, I did pay an electrician to do the work. And, I'm a-telling you people out there: If you don't know what you're doing with copper and all, don't pick this project as a nifty way to find out.
And, yeah, if the laws in your state calls for a building electrical inspection, do that thing. Contrary to popular belief, those inspectors aren't just there for the money: They're the backstop when an installer, licensed or not, does Something Wrong. And the inspector is put in there by Society and its Laws because Society has figured out that burned-down buildings aren't good for life, limb, and property values.

Products we're discussing on TMC...

About Us

Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.

Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.