The executive summary is that I have set up an EV charger function at a very difficult installation location, namely a construction site for a a friend’s house that is under construction. It is very different from the usual EV charger function. I am delighted at the successful results. Here are details.
The situation here is that I have been trying to be helpful to a friend who is building a house at a remote location. I have been trying to be helpful with the low-voltage wiring for this house. This includes:
- local area network (LAN) wiring
- security system wiring
- wiring to deliver power for window shades
- wiring for a surround-sound home theater area
- wiring for general stereo speaker areas
The LAN wiring is intended to support a variety of home automation functions at later times.
One of the challenges is that this construction site is at a very remote area, where there is very little EV charging infrastructure. I have had previous visits at this construction site to try to help with low-voltage wiring. In the most recent previous visit, the EV charging situation was so precarious that when I was returning towards home from this construction site with a plan of charging up the car at a Tesla supercharging station, I rolled into the charging station with a remaining driving range of one mile. Yes, only one mile.
Normally what I would do when I am visiting such a remote location is to install an EV charger. I would go onto Amazon and order up a Level-2 charger and get it shipped to the location ahead of time, and I would bring with me some appropriate materials such as six-gauge electrical wire and a two-pole circuit breaker. And I would install an EV charger.
But this is a house under construction. The house does not have electrical power yet. Eventually there will be electrical power in the house. But right now, the only electrical power at the house is extension cords that are plugged in at a pedestal that is some distance from the house. The pedestal is a so-called “disconnect panel” which is presently serving as a source of temporary electrical power for the construction site.
My friend who is building the house has done all the right things so that when the house is completed he will be able to have an EV charger in his garage. For example he has already run six-gauge cable to the place in the garage where he would install an EV charger. But that is months from now. When that time comes, I plan to return to the house to install the EV charger. But the situation right now is that we cannot really do a traditional installation of an EV charger. So what I am installing is something called a NEMA 14-50 receptacle. Here is what it looks like:
Back before EVs became “a thing”, this kind of receptacle was commonly used for electric ovens and for recreational vehicles. The purpose of this receptacle is to provide as much as 50 amps AC at 208 volts or 240 volts. The top connection is for the neutral wire, the bottom connection is for the ground wire, and the left and right connections provide 208 volts or 240 volts. In an ordinary residential setting this will be 240 volts.
A smart homeowner will, as a general matter, never use this or any other receptacle as a way of supplying power to an EV charger because it is smarter to hardware the EV charger. The hard-wiring permits the homeowner to configure the EV charger to run at a higher power level as compared to what the homeowner would be able to do if the EV charger were powered with a receptacle.
But as I say, this is not the usual situation. This is not a completed house with ordinary electrical power. This (partially completed) house does not even have “temp power” in any of the in-wall wiring. Right now the only electrical power around this construction site is provided by extension cords.
Right now at this construction site, the only source of power is what is called a “disconnect pedestal” that is some distance from the house. The disconnect pedestal is presently providing temporary power for the construction site, because it provides electrical receptacles where extension cords are plugged in. The extension cords that run to various destinations around the site.
What I did just now is to install the NEMA 14-50 receptacle at this pedestal, in an electrical box that is made for outdoor installation. The box has a swinging cover that can close over an in-use plug and can protect the plug from the elements. Here is what this kind of box looks like:
Some owners of Tesla cars will carry with them at all times a “mobile connector” and a “NEMA adapter bundle” set of power cords so that the mobile connector can get plugged in when it is needed. That’s what I do. The mobile connector looks like this:
The NEMA adapter bundle looks like this:
With the Tesla mobile connector, you pick one of the NEMA adapters to match whatever kind of receptacle is available, and you plug the adapter into the mobile connector. For the connection you see in these pictures, I picked the one marked in green. It has an NEMA 14-50 plug which I plugged into the newly installed NEMA 14-50 receptacle. As you can see, the mobile connector has a long cord with a plug that you can plug into the car’s charging port.
Some people who drive non-Tesla cars bring a similar travel charger with them in the car. Here is an example of such a travel charger:
This travel charger can get power from a NEMA 14-50 receptacle or from other kinds of electrical outlets.
In this picture you can see what I installed, which is the NEMA 14-50 receptacle and box. I suppose I could have installed an EV charger at this outdoor location. Some months from now, when the house is completed, I do plan to install an EV charger, inside the garage of the house. But right now I wanted to proceed economically. The economical way to proceed was to install this NEMA 14-50 receptacle, which in the future can be used for a house guest who arrives in an RV.
If you look very closely you can see the mobile connector hanging down from the box that I installed.
Here you can see part of the construction site. You can see my car parked nearby. You can see the Tesla travel charger (mobile connector). You can see the long cord and charging plug which is plugged into the charging port of my car.