Introduction: Installing a Tesla EV Charger
The beauty of electric vehicles (EV) is that your home has a built in supply of "fuel" stations. In the United States, most of our outlets are rated at 15-20 Amps and 120 Volts. While these outlets can charge a vehicle, charging times can easily stretch into days if you're adding significant range to your vehicle. The next step up from the standard wall outlet is something like a dryer or stove outlet, which are typically rated between 30 and 50 Amps at 240 Volts. Using these outlets, you can add significant range during overnight charging.
However, if you want to take things to the next level you'll want a dedicated EV charger. Dedicated EV chargers typically supply up to 50 Amps at 240 Volts and can be hardwired into your home or garage wiring. Instead of running a separate charging cable between an outlet and the car, these chargers have built in charging cables. They can also typically be used outdoors. If you have multiple EVs, some dedicated chargers can communicate with each other and share power to ensure your home's power supply is never overloaded. Some chargers include Wifi connectivity so that you can remotely monitor your car's charging.
Tesla produces what are arguably the most desirable EVs on the market today and they sell a branded EV charger, which I installed in my garage. Although this Instructable will be describing my experience in installing a Tesla charger, the steps should be similar to those required for another brand of charger.
This project is quite straightforward if you have a basic understanding of household wiring and your local electrical codes. However, if you are uncomfortable wiring high-current, high-voltage power, please hire a licensed electrician to do this installation.
Phillips and flathead screwdrivers
T10 and T20 security drivers (specific to Tesla wall charger)
Screws for attaching charger to wall
Red, black, & white individual-conductor stranded wire (8 gauge or lower recommended)
240V circuit breaker (40A or greater recommended)
PVC or metallic conduit
Tools to cut and install conduit (miter saw or hacksaw, drill or driver)
PVC primer and cement (if PVC conduit is used)
Fish tape (for pulling wire through conduit)
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Step 1: Opening Up the Charger
After removing the charger from the box, the first step is to remove its front cover. There are two covers on the Tesla charger. The first (outer) cover is primarily for looks and it is removed by first removing a small T10 Torx screw located on the bottom of the charger. With this screw removed, the cover is still attached by 6 small plastic clips around its edges. Beginning on one side near the bottom of the charger, I carefully pried up on the edge of the cover until the plastic clips began to release. I worked my way around the cover being careful to not damage the plastic. After all of the clips release, the outer cover lifts off the charger.
Inside the outer cover is an inner, weathertight cover. This cover is secured with six T20 security pin Torx screws. After removing these screws, the inner cover lifts off.
Step 2: The Baseplates
The Tesla charger comes with two baseplates or mounting brackets. The low-profile bracket is used if your conduit will enter the charger from the bottom or rear, while the top entry bracket is used when the conduit enters through the top. Since the charge cord is designed to be looped around the charger when not in use, the deeper top entry bracket sets the charger further off the wall allowing room for both the top entry conduit and the looped cable.
If you are using the top entry bracket, there is a separate terminal block with pre-attached leads inside the bracket. Wiring from your panel should terminate at this terminal block and the pre-attached leads will enter the rear of the charger and attach to the terminals in the charger. For more information on the special instructions for the top entry bracket, see Tesla's installation guide.
Step 3: Mount the Charger
Since my conduit would be entering the charger from the bottom, I chose the low-profile bracket. Before mounting the charger, an appropriate location should be selected. First make sure that the cord will reach to the vehicle's charge port. Typically this means mounting the charger on the side of the garage or parking space adjacent to the car's charge port. Tesla recommends a mounting height of 4 feet above the floor with at least 8 inches of clearance all around to allow for hanging of the cord.
Once a suitable location was selected, I mounted the low-profile bracket to the wall by driving screws through the six mounting holes. Since the brick wall I was mounting to was quite brittle, I first attached a plywood baseplate to the wall using Tapcons and then screwed the low-profile bracket to the plywood.
If you are mounting to a studded, drywall wall, I would recommend driving the screws on one side of the bracket into a stud and using strong drywall anchors for the remaining three holes. For concrete or concrete block walls, Tapcon-type screws should work well. For brick walls, Tapcon screws may work, but if the brick is very soft you may need to use epoxy to bond the fasteners.
After the mounting bracket was leveled and installed, the charger simply slid onto the four mounting tabs on the bracket. The charger was secured to the bracket using the included Torx screws. Tesla includes little plastic covers for these screws to make everything look good.
Step 4: Run the Conduit
The charger and top entry bracket include threaded connections for 1" conduit. If you are mounting the charger on a finished, studded wall you may be able to run un-protected Romex-type wire directly into the back of the charger, but for all other wiring configurations you will need to run conduit between the electrical panel and the charger.
When selecting conduit there are several factors which should be considered. First is the conduit size, which is dictated by the number and size of the wires running through it and the type of conduit used. I've included four tables, which show the number of THHN/THWN stranded wires of various gauges (diameters), which can be passed through four common types of conduit.
The second conduit selection factor is the conduit type. Electrical metallic tubing (EMT) is one of the most widely used conduit types for interior applications, although flexible metallic conduit (FMC) or rigid metal conduit (RMC) are also used. Depending on your application, you may also be able to use rigid PVC conduit, although codes on its use vary. PVC is ideal in corrosive environments and for underground use, but it can become brittle when exposed to sunlight or very cold temperatures. It is also not as structurally stable and must be supported more often. PVC can also be more easily damaged if impacted.
Despite the drawbacks of PVC, I ended up using it for my charger as the conduit will not be exposed to severe environmental conditions and the risk of impaction is low. Since I would be running three 8 gauge and one 10 gauge wire, a 3/4" conduit was large enough. I reduced the 1" conduit leaving the charger to 3/4" and cut, fitted, and secured the sections needed to reach the sub-panel in my garage.
Step 5: Select and Pull the Wire
With the conduit in place, my focus turned to pulling the wires. I selected the wire gauge based on the desired current load to the charger. I've included a handy table that I used to select the wire gauge based on the wire type and current. Using this table, I found that an 8 gauge, THHN-type wire could handle up to 55 amps, which was slightly greater than the 50 amp breaker I planned to use. After further research, I found that a 10 gauge THHN wire would be sufficient for the ground, although I ended up not using that wire as I'll discuss later.
To pull the wire, I pushed my steel fish tape through the conduit from the sub panel to the charger. I used electrical tape to secure the wires to the fish tape and pulled all four wires through to the sub panel. If your conduit has a large number of bends, you may want to use a size larger conduit to allow the wires to pull more easily.
Step 6: Connections in the Sub Panel
Before you do any electrical work in a sub panel, you should flip the breaker on the main panel supply power to the sub panel. If you're working on a main panel you may not be able to turn off the power to it. A licensed electrician will know how to work on a live panel safely.
After stripping the ends of the wires, they were attached to their appropriate locations in the sub panel. These connections can be seen in the image. The white wire attaches to the neutral bar, which should be grounded. The green wire attaches to the ground bar. The black wire is for Phase 1 and the red wire Phase 2. These phases attach to the two terminals of a 240V breaker. In my case, I added a new 50 amp breaker for the charger.
Note that this represents what is typical of a two-phase installation in the United States. The Tesla installation guide should be consulted for installation on different electrical systems.
Step 7: Connections in the Charger
There are connections for the neutral and two phase wires in the charger. Remember that ground that I said I didn't need to run? Since the Tesla charger requires that your neutral is grounded, it does not utilize a separate ground wire. Instead of pulling this wire out, I simply capped it with a wire nut and pushed it out of the way.
The neutral wire attaches to a small aluminum block on the circuit board. The two phase wires are inserted into terminal connectors on the side of a large, green, plastic block. There are two Phillips screws in the top of this block, which are used to secure the phase wires. Be sure to loosen these screws fully before inserting the wires. The first time I inserted the wires, the screws were not loose enough and the wires weren't secured when the screws were tightened. After tightening the screws, give the wires a tug to make sure they are secure.
Step 8: DIP and Rotary Switches
Inside the charger are two DIP switches, which are used to tell the charger how it is wired. While I wired the charger using two 120V phases (line to line) configuration, you can also wire it using a single 240V phase returning to a neutral (line to neutral). The configuration of the DIP switches for both of these wiring configurations can be seen in the first image.
To the right of the DIP switches is a rotary dial, which is used to set the maximum current that the charger can draw. You simply work you way down the table in the second image until you find the circuit breaker size used for the charger. In my case, I used a 50 amp breaker, which meant I set the rotary dial to position 8.
Step 9: Closing the Charger
With the wiring finished, the charger can be closed back up. Before you re-attach the inner cover, be sure to attach the ribbon cable to the circuit board on the inside of the cover. The inner cover is secured using the same T20 security Torx screws removed earlier. Finally, the outer cover is snapped back onto the charger by pushing along its edges. This cover is secured at the bottom by the single T10 Torx screw.
Step 10: That's It
After the covers are installed, the circuit breaker supplying power to the charger can be flipped on and the charger is ready for use. When it is fired powered up, the Tesla charger will go through a short boot sequence. Once finished, a solid green light will display through the window in the front of the unit.