Wall charger setting

Wall charger setting

I need clarification for the rotary switch position for the Wall Connector I just had installed for my Model 3. Is it harmful to have it set at position ‘B’ (64amp max output) or is it required to have it set at position ‘9’ (48 amp max output)?

RSavage_92024 | May 29, 2018

The rotary switch is actually an input setting....the HPWC and your car will negotiate the proper output. Match your switch setting to the circuit you are on.

ghoop1 | May 29, 2018

I set mine at position D (80amps) and just let the car figure it out. The Model 3 will only go to 48 amps. I have seen 46 MPH added back to the car with this setup.

johnse | May 29, 2018


I presume you installed that on a 100A circuit?

SUN 2 DRV | May 29, 2018

Rsavage +1 Yes set the Wall Connector switch based on the CIRCUIT WIRING and BREAKER size you have. The car will draw what it needs up to that level.

Rocky_H | May 30, 2018

@David.McCormack, This isn't a preference thing, where you get to decide what you feel like setting that to. It is as @SUN 2 DRV is saying. You have picked a circuit size for your install. You set the wall connector switch to match the circuit size.

Parker.andy | October 24, 2018

So I had my electrician install my Tesla wall charger and for some reason, I was just getting 12 amps but had a 60 amp circuit. So first, to get the cover off the unit (not the silver one on top but the black one underneath), you need a T-20 "security" driver - NOT the standard T-20 (3 trips to the hardware store figured that out). Second, the little dial that should be at 9 (with a 60 amp service) is VERY SMALL. But, all that said, I'm now charging at 48 amps. The moral? Make sure you have a Tesla-approved electrician install it.

shwelch | October 24, 2018

My electrician had never installed the wall charger, but just read the manual and set it up with no problems. Cheaper than a Tesla Approved electrician. He said it was straightforward and had it up in less than an hour.

chuck | October 24, 2018

Your Model 3 will not benefit from settings above 9. However, if your wiring and circuit breaker support a higher setting, then Model Ss or Xs you might buy in the future or which guests might arrive in can benefit.

Mozart | October 24, 2018

As others have said, set the rotary switch to position B if you have an 80 amp breaker and the appropriate size wire. The car will draw 48 amps

cwo911 | January 11, 2020

I recently had a Tesla wall charger installed on a 60 amp circuit but I’m only getting a maximum of 32 MPH with a draw of 32 amps. They pot is is set at 9. Is this the max MPH I can expect, or should I be getting around 42 to 48 MPH? Would changing the two vertical switches give me greater MPH?

Big_Ed | January 11, 2020

If you have an SR or SR+ you are limited to 32 amps. If you have an LR or P you can go to 48 amps.

Tronguy | January 11, 2020

All right. I'm the EE here. (There's probably others).
To the Original Poster:
First, whatever it is you stick into a Tesla car socket, it tells the Tesla how much voltage and current is available. Whatever happens next, the Tesla won't draw more than what's available.
Second: The Tesla knows what it can suck down, max, and won't go over that.
Result: The weakest link wins.
So: A M3 SR can't draw more than 32A at 250VAC. A M3 LR or P can draw up to 48A at 250 VAC. For DC, that's a different story, and Superchargers and the car negotiate.
Third: The National Electric Code is run by a bunch of beady eyed people, in collusion with local governments everywhere, and society at large who vote for people who vote for laws, who have an interest in people Not Burning Down The House. It lowers property values.
NEC says, first, that the breaker box has to have the capacity to handle whatever load you've got in mind. So, one is not going to put a 100A breaker in a 100A panel unless one wants the local electrical inspector all over one's butt. 60A, maybe: Real electricians do load analysis according to code. I've got a 60A breaker in my 200A panel. The electrician and inspector were both happy.
Next thing: The breaker is rated for a given current, the wire gauge is supposed to be sized for that current, and so is the socket. So, if you have a NEMA5-15 socket, standard US 120 VAC wall socket, you'd best have a 15A breaker and wire to match.
Third thing: NEC says that max steady state current on a particular socket shall be no more than 80% of full load. If you think about that for 5 seconds, and it'll come to you. Run a 15A breaker at 15A and it'll pop, that's the point. So, max load on this example would be 12A, 80% of 15A.
If you plug a NEMA5-15 adapter into the Tesla Mobile Connector, the electronics in the connector will tell the Tesla computer this, and 12A is what you'll get. If you use a NEMA5-20 (plug and socket have one blade at right angles, and you'd better be using a 20A breaker and wire to match), then you'll get a 16A charging current.

Tronguy | January 11, 2020

Fine, wonderful. So, what about the TWC? TWC can handle a whole slew of different breaker sizes/wire gauges, from 20A up to 100A. You set the switches to match what you've wired into the breaker panel and the size of the breaker.
There are Model S's out there that can and will draw 80A, given the opportunity. The opportunity arises when the breaker panel can support a 100A breaker, such a breaker is installed, the correct wire gauge that can handle 100A is present, and the switches are set to 100A on the TWC. The bitty board in the TWC will talk to the car and the Model S, in this case, will draw 80A.
Suppose that the electrician frowns on 100A but says 60A is OK? Then, use a 60A breaker, wire for 60A, set the switches to 60A, and the Tesla Model S will draw no more than 48A, it being programmed by people who would rather not see your house make the evening news.
Same deal's pretty much the same for a M3. M3 SR will never draw more than 32A at 250VAC, that being the limit. LR and P can do 48A. So, if you want full speed for your LR, then you put in a 60A breaker, wire to match, and set the switches for 60, the M3 will check what's available, and won't draw more than 80% of 60A, which is 48A.
Using a bigger breaker and wire (say, the aforementioned 100A breaker and wire to match) isn't necessarily a bad idea. Some time down the road Tesla may make something that sucks down more power, so that might be useful. Further, the TWC can also be ganged with other TWCs on the same circuit breaker so one can charge multiple cars more or less at once without moving cables around, and I suppose the 100A service would help with that.
By all that's holy, though: Never set those switches for a higher current than what your breaker and especially wires can handle. That way lies smoke.

milesbb | January 11, 2020

" if you have a NEMA5-15 socket, standard US 120 VAC wall socket, you'd best have a 15A breaker"

not so, the code allows a NEMA 5-15 to be connected to a 20 amp breaker, actually this is a more common installation than NEMA 5-15 on a 15 amp breaker. 20 amp #12 awg wire is required on a 20 amp breaker. Reference Table 210.24 Summary of Branch-Circuit Requirements.

Tronguy | January 11, 2020

@milebb: Thanks for the correction. And, no, don't have the NEC standards near by :).

Big_Ed | January 11, 2020

"code allows a NEMA 5-15 to be connected to a 20 amp breaker"

Quite true. However, I believe there is one exception. If you attach a single outlet to a 20 amp breaker, it must be 20 amp rated. If you have more than one outlet on a circuit, the outlets can be any combination of 15 and 20 amp rated.

kaffine | January 11, 2020

Code allows 15amp outlets on a 20 amp breaker for residential as long as there is more than 1 outlet. The normal outlet is a duplex and counts as 2.

Commercial buildings however require 20 amp outlets. Not sure if this is a recent change or not.

If you actually take apart the outlet though most of the 15 amp outlets are really 20 amp the cover just doesn't have the extra slot to allow a 20 amp cord to plug in.

The switch in the Wall Connector gets set to the size of wire and breaker.

andy.connor.e | January 11, 2020


Not sure where you are getting your references from. Electrical code does not require 20A outlets in commercial buildings. The slot in the 20A outlet is there to differentiate that it is a 20A outlet, as regular 15A outlets do not have the slot. You are correct about your first point, 15A outlet is allowed on a 20A circuit per NEC-210.21(B)(3).

@Big_Ed is correct.

andy.connor.e | January 11, 2020

The only difference between the 15A and 20A really, is that 20A requires #12 wire, and 15A can use #14's.

kaffine | January 11, 2020


I was wrong. I knew I should have looked up the actual code reference then I would have realized it before I posted. I should learn to not rely on my memory.

bjrosen | January 12, 2020

The switch should be set to the proper rating for the circuit that it's attached to (80% of the circuit rating). The wall connector is going to be there for years, the current Model 3 is limited to 48A but you may have a different car in the future that can draw more. If you set the switch to 80A on a 60A circuit you won't notice anything wrong now but some day in the future you, or the next guy who owns your house, will plug in his 2030 Tesla and at the very least he will blow the circuit breaker, maybe worse if the circuit breaker doesn't function correctly.

andy.connor.e | January 12, 2020

Setting it to higher than the circuit rating will only result in disaster. Your circuit rating should not be lower than your protective device, in this case the breaker. If you are running a 60A circuit, you need #6 wires with a #10 ground. You are ok to use 3/4" Schedule 40 PVC conduit for that, but i would recommend doing it with MC cable.

Pg3ibew | January 12, 2020

As an electrician for 35 years, I am reading all of these comments and laughing.
I would never make a recommendation on how to do electrical work. Simply because there are many factors involved. Nothing is as COOKIE CUTTER as every one would like it to be.
All I can say is, it is awesome that the car knows how many amps to draw.

andy.connor.e | January 12, 2020

recommending wire size and conduit size is not recommending how to do it. Its just materials.

Pg3ibew | January 12, 2020

@andy, be careful what you recommend. Different types of wire, have different amperage ratings. THHN is different than RHW. There are dozens of types of wire. And there is also temp. ratings of wire.
There are also different amperage ratings based on length. As well as conduit Fill. Different locations call for different types of conduit. EMT, Rigid Gal, PVC.
Different municipalities may have more stringent rules then the NEC. NYC is one of those places.

Like I said, electrical work is not cookie cutter.

Pg3ibew | January 12, 2020

I can promise you this... Even With 35 years of experience, I will NEVER recommend anything to anyone when it comes to electricity.

Pg3ibew | January 12, 2020

Aluminum vs. Copper.

Pg3ibew | January 12, 2020

Solid wire vs. Stranded wire.

andy.connor.e | January 12, 2020

You're the electrician, and im the engineer. I am well aware of the different wire types. I took those numbers based on THHN 75°C rating. Conduit type does depend, but thats why i said i recommend MC cable from the panel to the outlet. I can tell you exactly what materials you need, but i am not one who does field work. Although, i am one to inspect field work.

andy.connor.e | January 12, 2020

Alright dude. i didnt get into the weeds that deep because no one was asking for anyone to be that specific. If you want me to get deep into details about everything i can but that was not the message i was getting that people wanted to hear.

Big_Ed | January 12, 2020

I'm thinking a guy with IBEW in his username probably knows about wiring.

andy.connor.e | January 12, 2020

ya because someones username totally represents their knowledge.

Pg3ibew | January 12, 2020

@andy, I am NOT doubting your intellect. Not one bit. I am doubting the intellect of the masses.
Do you think the average home owner is looking for THHN 75C rated stranded copper?
I see the standard home owner finding STUFF in their dead uncles basement. And see the #6 on the wire. And saying ANDY.CONNOR said 6 wire. So this is good. But.... the wire is aluminun and Asbestos coated from 1938.

I guess I am just saying, never under estimate the stupidity of the masses.

Carry on.

Pg3ibew | January 12, 2020

@Big and @andy. I am not saying I know anything about electrical work.
I am smart enough to know, the masses are not that smart.

andy.connor.e | January 12, 2020

"I guess I am just saying, never under estimate the stupidity of the masses."

Yep that is pretty much the case

andy.connor.e | January 12, 2020

I guess im just trying to be helpful than just telling people to go ask an electrician, because myself included, are not interested paying someone to give them info.

Lonestar10_1999 | January 12, 2020

If you read the NEC Handbook, you’ll see that it contains the entire National Electrical Code plus an explanation of how the code is applied. The explanation has detailed illustrations and annotations so you can make informed decisions on constructing your project. I appreciate those on the forum contributing their knowledge and expertise.

Common sense dictates that if you are inexperienced and unsure, you will hire a qualified professional to build the project and have the finished project inspected and permitted by the municipal code enforcement officer.

Scrannel | January 12, 2020

Well, without contradicting "the world is an idiot" knock-down, I will argue it's not hard to be smart (just easier to be stupid). Needed to put in a 14-50 for my Tesla, and a generator transfer setup for those pesky outages during California wild fires. My local electrician couldn't be bothered, either because there was more money to be made with all the burned homes... or the solstice/UFO alignment over Malibu wasn't right for his head. So, did it all myself, got it signed off by local authority (all perfect), but they did catch something NOT to code: put in by a certified electrician for prior owner, then never signed off. So, stupid-world can apply to card-carrying electricians as well. Oh yeah, I'm a screenwriter.

Lonestar10_1999 | January 12, 2020

I installed a NEMA 14-50 outlet in my garage using 3-#6 romex with a 2P-50A breaker. But if I ever wanted to upgrade to a Tesla wall charger, I would use 3-#3 romex and a 2P-100A breaker. Such an installation (assuming the house electrical system can handle it) would allow for the maximum charge rate regardless of Tesla model connected. The wall charger also allows for a second charger cable for simultaneous charging of two cars. Imagine a husband and wife come home from work and each can recharge sharing the single wall charger.

You don’t have to be a genius like Elon to know a happy wife is a happy life.

lbowroom | January 12, 2020

Pretty sure you can carry 60A 240V over Ethernet or HDMI

kevin_rf | January 12, 2020

Lbrowroom, I've always found running 60a over 26awg nicrome wire provides the best mix to keep the charge port warm and happy.

kevin_rf | January 12, 2020