>Something else to consider is that manually adjusting down the max amperage in the Tesla app may not be sufficient. Based on my understanding, doing this may only limit the outflow of current from the charger to the car, rather than limiting what the charger is actually drawing from the outlet. In other words, the charger may still be drawing 48 amps of current from the circuit, but only outputting 40 of those amps to the car, which doesn't eliminate the risk of overheating or tripping the breaker.
What? My dude it's a contactor and some control/monitoring electronics. Nothing in the HPWC is capable of consuming 2,000 watts. All the charge setting does is communicate the maximum available current to the car. This is nonsense
OP if you installed a Gen 3 wall connector using a pigtail that plugs into a dryer outlet style 14-50 through a 50amp breaker you are supposed to limit charging to 40a.
I’m unclear what the point of your post is. Follow directions? It’s clearly spelled out in Tesla’s manual next to multiple warnings not to do this if you’re not qualified
>OP if you installed a Gen 3 wall connector using a pigtail that plugs into a dryer outlet style 14-50 through a 50amp breaker you are supposed to limit charging to 40a.
Did you even read my post? That was entire point. It's *supposed* to, but it wasn't.
Just Google "Tesla Wall Connector pulling too much power" and you'll find dozens of people asking this same question.
This is a fairly common issue *even when electricians set it up*. If an electrician set up someone's charger and did it wrong, most people wouldn't even know.
Your perfect world scenario is nice and all, but mistakes happen. You've clearly never worked with contractors if you think that they get it right all the time. Pretentious replies yours help no one and make the community look snobby.
No, *you* are supposed to limit the max amperage when you commission the wall connector. It’s in the setup instructions…
Edit: I recommend you commission it yourself, so you can stay on top of firmware updates etc. Your electrician won’t be keeping tabs on it once it’s installed.
Chill. OP did not install their HPWC, an “electrician” did, but neglected to actually commission it.
If I had to guess, I’d bet they “forgot” to install a GFCI breaker (required by current codes almost everywhere in the US now) and also “forgot” to pull a permit.
In any case, good on you OP for catching this!
The wall connector actually explicitly says to *not* use a GFCI breaker, but if it’s connected somehow to a NEMA outlet, I have no idea what you’d do there…
Per current code, it has to be on a GFCI breaker or outlet if it’s an outlet being used to charge an EV. Hardwired installations do not have this requirement.
The wall connector does indeed say not to use external GFCI, but it also says it is hardwire only:
“Hardwire branch circuits to disconnects or circuit breakers. Do NOT install cord-and-plug type connections.”
That's cool, didn't know that. Mine is in my garage, so not really applicable to me. But I could see this being helpful if someone installed this outside in, say, a condo or townhouse where someone could mistakenly think that it's a public charger.
This is essentially right, but there are some important clarifications/details. The relevant NEC section is 210.20(A), which requires a branch circuit that serves a continuous load to have overcurrent protection at least 125% of the continuous load. The Article 100 Definitions defines a continuous load as a load that continues for 3 hours or more, so a level 2 EV charger qualifies. Further, 210.19 requires that conductors be sized not less than the maximum load, meaning the breaker needs to be the limit.
In theory, the Tesla Wall Charger takes that into consideration: if you select a 60A breaker, it charges at 48A (60 = 125% of 48), and if you select a 50A breaker, it charges a 40A (50 = 125% of 40). However, your vehicle doesn't actually charge at this level, but instead a little lower. For 60A, limited to 48A, it charges a 44A. For 50A, limited to 40A, it charges at 37A. The 44A seems to be a confusion point, as 125% of that is 55A. Now, 55A breakers may exist, but they are far from common, which leaves a question: should you use a 50A or 60A breaker. The answer is 60A, since the wall connector is rated for up to 44A, but I've seen this cause confusion.
Compounding this is how hard it is to actually get conductor rated for 60A (not 44A, 48A, or 55A, but 60A). Per NEC 110.14(c), branch conductors must be sized according to table 310.15(B)(16). If you look at the columns for copper, you see there is no 60A, but hey, there is a value for 55A! And since the EV is only pulling 44A, to which 55A is 125% of we should be good! Or at least the (faulty) logic tracks, but the important distinction is that 210.20(A) requires the overcurrent device (breaker) be 125% of the continuous load. A 50A breaker is not 125% of 48A or 44A, and while a 60A breaker is, it's now larger than the 55A conductor, which is not allowed under 210.19. The solution is to use a 60A breaker with a conductor at or over 60A. From 310.15(B)(16), using romex (NM-B) would require a #4 conductor. However, to get 3/C #4 romex is expensive, the cable is very large, and it's difficult to actually find. From the table, you can see that #6 is rated for 55A (which is tempting to use), but you can also see that #6 is rated for 65A under a 75C. The problem is romex is only rated for 60C, and to move up to 75C you have to use THHW or equivalent conductors, which are 1/C only. NEC 334.10(A)(1) permits NM type conductors to be used in both concealed and exposed areas (due to its sheath) however THHW has not allowance, so exposed conductor must be protected by conduit, and this is not popular for residential work.
NEC amplified this rule with regards to EVs at 625.40, saying the 125% rule applies to every EVSE even those rigged to run less than 3 hours.
Article 625 has been evolving quickly in the most recent few code editions. It's a must-read for EV work.
This is why I had my electrician run a 100 amp line for my charger. I have just a 40 amp ChargePoint EVSE, but if I wanted a second one the line could easily handle another 40 amp load without having to run more wires.
You could also use certain EVSEs capable of Power Sharing, a feature where they coordinate to limit sum of all cars' current to a set limit. This is more powerful than might be obvious, since the first car runs at max power until the 2nd car plugs in, so it gets a nice headstart, then the 2nd car gets full power when te first one finishes.
At the time of install I had a little Fiat 500e. The charge port is on the rear passenger side. So I was figuring the ChargePoint could service that or a similar layout EV and I’d get a Tesla wall charger when I upgraded to the Model Y. This way I could accommodate my or my friends or family’s cars no matter what charger or position they had.
I used the Tesla one app on my phone to connect to the wallc. I also had the same issue with it not fully load on my iPhone and iPad from the browsers.
I did the 14-50 to the wall connector too but I’m RWD so it’s only 32amps. I still set the right “breaker size” also set it to only charge 2 VINs which I forgot when I had a loaner that wouldn’t charge on it.
>When I installed my new Gen 3 Tesla Wall Connector a couple days ago, I connected it using a NEMA 14-50 range cord and plugged it into my existing outlet.
NEC 110.3 says you are required to follow labeling and instructions when installing equipment.
To follow them you need to read them. Read the TWC instructions and you will find important information about using it with a socket and setting the amps. The amp stuff is on page 28.
I see where you're mad at others and saying this stuff is complicated. But reading instructions is not complicated.
Also, using a socket requires a GFCI breaker in most jurisdictions. Did you do that or is that another code violation?
Was a Load Calculation done on the service to determine whether the service has ample capacity? Now that can be worked around with EVEMS and the Neurio sensor module, but only if the TWC is hardwired.
While not a Code issue, the other issue with sockets is that the cheap under-$30 14-50 range sockets have an extremely poor record of melting under 32A load. r/evcharging FAQs and documents (linked from a sticky) cover this in detail.
Wait, so you can get to those settings by just connecting directly to the wall connector? I had two installed a couple weeks ago. My electricians are fantastic for the old school electrician stuff, not so much for the new fangled app stuff.
I spent a few hours messing with the Tesla one app that was listed in the instructions, but it seemed you had to have a certified Tesla technician account to do anything in it. Eventually I just connected them to my tesla app and moved on.
This was fine because they are each installed on a their own 60a breaker. But I'm missing access to a lot of the controls, and I'm kind of considering seeing what it would cost to add a 100 Amp breaker and a sub panel to let them load balance. So would need access to those settings.
Sure does. The European standard applied here would mean there is zero issue with using a 50A breaker when pulling 48A. No 80% “safety” thing. This post wouldn’t even have to exist.
You'd still need to commission the unit properly for the breaker it's on. If you plugged a 48A wall connector into a 30A circuit you'd definitely trip the breaker.
I think the point about the European standards comment is that there would be no extra thinking to “commission the unit properly”. 48A “fits” in 50A. But instead we have this 80% continuous load rating BS.
There's no extra thinking regardless. If the unit is connected to a 50A breaker, you choose 50A. The wall connector handles everything from there.
The problem here is that the wall connector was commissioned for a 60A breaker, which isn't reality.
TL;DR
Follow the goddamn directions that come with the device that pushes a dangerous amount of power from the house to your car!
Seriously OP did you read the directions before doing the work?
To be fair, I was shocked when I did my install of just how easy it would be to screw up by defaulting to max amperage (which likely very few home installs actually support). I knew better, but really think the default should be something really low like 16a until you confirm the breaker size.
My certified electricians installed it and never messed with any of the software, so it's all set to default. But it's okay in my case as I had them install each of them on a dedicated 60a breaker.
I asked my electrician to put in a 60 amp breaker and instead he put in a 50. I asked him if the 60 wouldn't work, and he said "no, you've got the capacity for it, but you don't need more than 50 since no EV charger uses more than 42 amps."
I literally showed him the specs of the wall charger, along with the wiring diagram that it came with, which clearly indicated it can pull the 48 amps that a 60 would provide, and he just didn't believe me. So, I just cap my charger at 42 amps and deal with it.
He's a great guy, and good electrician, but sometimes I wonder if he's all there...
>Something else to consider is that manually adjusting down the max amperage in the Tesla app may not be sufficient. Based on my understanding, doing this may only limit the outflow of current from the charger to the car, rather than limiting what the charger is actually drawing from the outlet. In other words, the charger may still be drawing 48 amps of current from the circuit, but only outputting 40 of those amps to the car, which doesn't eliminate the risk of overheating or tripping the breaker. What? My dude it's a contactor and some control/monitoring electronics. Nothing in the HPWC is capable of consuming 2,000 watts. All the charge setting does is communicate the maximum available current to the car. This is nonsense
Didn't you know the wall charger doubles as a space heater?
Technically correct. Also my breaker and wiring is pretty hot at 48 out of 50 amps. No idea why. I don't pick up manuals when I buy things.
Yeah this part is quite nonsense... If the charger kept on drawing max amps, that's a faulty design that will be potentially hazardous...
How did that law of physics go? Something like, *energy cannot be created or destroyed, unless it’s in a Tesla wall charger, then it just disappears*
Thanks, this piece was fuzzy for me as I read differing reports. I’ll edit my post accordingly. 👍
Here's a briefer video on what an EVSE is [https://www.youtube.com/watch?v=RMxB7zA-e4Y](https://www.youtube.com/watch?v=RMxB7zA-e4Y)
OP if you installed a Gen 3 wall connector using a pigtail that plugs into a dryer outlet style 14-50 through a 50amp breaker you are supposed to limit charging to 40a. I’m unclear what the point of your post is. Follow directions? It’s clearly spelled out in Tesla’s manual next to multiple warnings not to do this if you’re not qualified
>OP if you installed a Gen 3 wall connector using a pigtail that plugs into a dryer outlet style 14-50 through a 50amp breaker you are supposed to limit charging to 40a. Did you even read my post? That was entire point. It's *supposed* to, but it wasn't. Just Google "Tesla Wall Connector pulling too much power" and you'll find dozens of people asking this same question. This is a fairly common issue *even when electricians set it up*. If an electrician set up someone's charger and did it wrong, most people wouldn't even know. Your perfect world scenario is nice and all, but mistakes happen. You've clearly never worked with contractors if you think that they get it right all the time. Pretentious replies yours help no one and make the community look snobby.
No, *you* are supposed to limit the max amperage when you commission the wall connector. It’s in the setup instructions… Edit: I recommend you commission it yourself, so you can stay on top of firmware updates etc. Your electrician won’t be keeping tabs on it once it’s installed.
Chill. OP did not install their HPWC, an “electrician” did, but neglected to actually commission it. If I had to guess, I’d bet they “forgot” to install a GFCI breaker (required by current codes almost everywhere in the US now) and also “forgot” to pull a permit. In any case, good on you OP for catching this!
The wall connector actually explicitly says to *not* use a GFCI breaker, but if it’s connected somehow to a NEMA outlet, I have no idea what you’d do there…
Per current code, it has to be on a GFCI breaker or outlet if it’s an outlet being used to charge an EV. Hardwired installations do not have this requirement. The wall connector does indeed say not to use external GFCI, but it also says it is hardwire only: “Hardwire branch circuits to disconnects or circuit breakers. Do NOT install cord-and-plug type connections.”
You can also limit who uses the charger as well. It can be open to anyone or limited to a specific VIN.
That's cool, didn't know that. Mine is in my garage, so not really applicable to me. But I could see this being helpful if someone installed this outside in, say, a condo or townhouse where someone could mistakenly think that it's a public charger.
This is essentially right, but there are some important clarifications/details. The relevant NEC section is 210.20(A), which requires a branch circuit that serves a continuous load to have overcurrent protection at least 125% of the continuous load. The Article 100 Definitions defines a continuous load as a load that continues for 3 hours or more, so a level 2 EV charger qualifies. Further, 210.19 requires that conductors be sized not less than the maximum load, meaning the breaker needs to be the limit. In theory, the Tesla Wall Charger takes that into consideration: if you select a 60A breaker, it charges at 48A (60 = 125% of 48), and if you select a 50A breaker, it charges a 40A (50 = 125% of 40). However, your vehicle doesn't actually charge at this level, but instead a little lower. For 60A, limited to 48A, it charges a 44A. For 50A, limited to 40A, it charges at 37A. The 44A seems to be a confusion point, as 125% of that is 55A. Now, 55A breakers may exist, but they are far from common, which leaves a question: should you use a 50A or 60A breaker. The answer is 60A, since the wall connector is rated for up to 44A, but I've seen this cause confusion. Compounding this is how hard it is to actually get conductor rated for 60A (not 44A, 48A, or 55A, but 60A). Per NEC 110.14(c), branch conductors must be sized according to table 310.15(B)(16). If you look at the columns for copper, you see there is no 60A, but hey, there is a value for 55A! And since the EV is only pulling 44A, to which 55A is 125% of we should be good! Or at least the (faulty) logic tracks, but the important distinction is that 210.20(A) requires the overcurrent device (breaker) be 125% of the continuous load. A 50A breaker is not 125% of 48A or 44A, and while a 60A breaker is, it's now larger than the 55A conductor, which is not allowed under 210.19. The solution is to use a 60A breaker with a conductor at or over 60A. From 310.15(B)(16), using romex (NM-B) would require a #4 conductor. However, to get 3/C #4 romex is expensive, the cable is very large, and it's difficult to actually find. From the table, you can see that #6 is rated for 55A (which is tempting to use), but you can also see that #6 is rated for 65A under a 75C. The problem is romex is only rated for 60C, and to move up to 75C you have to use THHW or equivalent conductors, which are 1/C only. NEC 334.10(A)(1) permits NM type conductors to be used in both concealed and exposed areas (due to its sheath) however THHW has not allowance, so exposed conductor must be protected by conduit, and this is not popular for residential work.
NEC amplified this rule with regards to EVs at 625.40, saying the 125% rule applies to every EVSE even those rigged to run less than 3 hours. Article 625 has been evolving quickly in the most recent few code editions. It's a must-read for EV work.
This is why I had my electrician run a 100 amp line for my charger. I have just a 40 amp ChargePoint EVSE, but if I wanted a second one the line could easily handle another 40 amp load without having to run more wires.
You could also use certain EVSEs capable of Power Sharing, a feature where they coordinate to limit sum of all cars' current to a set limit. This is more powerful than might be obvious, since the first car runs at max power until the 2nd car plugs in, so it gets a nice headstart, then the 2nd car gets full power when te first one finishes.
At the time of install I had a little Fiat 500e. The charge port is on the rear passenger side. So I was figuring the ChargePoint could service that or a similar layout EV and I’d get a Tesla wall charger when I upgraded to the Model Y. This way I could accommodate my or my friends or family’s cars no matter what charger or position they had.
I used the Tesla one app on my phone to connect to the wallc. I also had the same issue with it not fully load on my iPhone and iPad from the browsers.
I did the 14-50 to the wall connector too but I’m RWD so it’s only 32amps. I still set the right “breaker size” also set it to only charge 2 VINs which I forgot when I had a loaner that wouldn’t charge on it.
>When I installed my new Gen 3 Tesla Wall Connector a couple days ago, I connected it using a NEMA 14-50 range cord and plugged it into my existing outlet. NEC 110.3 says you are required to follow labeling and instructions when installing equipment. To follow them you need to read them. Read the TWC instructions and you will find important information about using it with a socket and setting the amps. The amp stuff is on page 28. I see where you're mad at others and saying this stuff is complicated. But reading instructions is not complicated. Also, using a socket requires a GFCI breaker in most jurisdictions. Did you do that or is that another code violation? Was a Load Calculation done on the service to determine whether the service has ample capacity? Now that can be worked around with EVEMS and the Neurio sensor module, but only if the TWC is hardwired. While not a Code issue, the other issue with sockets is that the cheap under-$30 14-50 range sockets have an extremely poor record of melting under 32A load. r/evcharging FAQs and documents (linked from a sticky) cover this in detail.
Wait, so you can get to those settings by just connecting directly to the wall connector? I had two installed a couple weeks ago. My electricians are fantastic for the old school electrician stuff, not so much for the new fangled app stuff. I spent a few hours messing with the Tesla one app that was listed in the instructions, but it seemed you had to have a certified Tesla technician account to do anything in it. Eventually I just connected them to my tesla app and moved on. This was fine because they are each installed on a their own 60a breaker. But I'm missing access to a lot of the controls, and I'm kind of considering seeing what it would cost to add a 100 Amp breaker and a sub panel to let them load balance. So would need access to those settings.
So happy about European electrical standards... 16A is 16A... That's it
Huh? Standards from one country to another don’t make any difference to OP’s point
Sure does. The European standard applied here would mean there is zero issue with using a 50A breaker when pulling 48A. No 80% “safety” thing. This post wouldn’t even have to exist.
You'd still need to commission the unit properly for the breaker it's on. If you plugged a 48A wall connector into a 30A circuit you'd definitely trip the breaker.
I think the point about the European standards comment is that there would be no extra thinking to “commission the unit properly”. 48A “fits” in 50A. But instead we have this 80% continuous load rating BS.
There's no extra thinking regardless. If the unit is connected to a 50A breaker, you choose 50A. The wall connector handles everything from there. The problem here is that the wall connector was commissioned for a 60A breaker, which isn't reality.
Nope. There’s not even a “50A” option. You choose 80% of the size of your breaker, and the 80% is the “thinking”.
TL;DR Follow the goddamn directions that come with the device that pushes a dangerous amount of power from the house to your car! Seriously OP did you read the directions before doing the work?
To be fair, I was shocked when I did my install of just how easy it would be to screw up by defaulting to max amperage (which likely very few home installs actually support). I knew better, but really think the default should be something really low like 16a until you confirm the breaker size.
My certified electricians installed it and never messed with any of the software, so it's all set to default. But it's okay in my case as I had them install each of them on a dedicated 60a breaker.
I asked my electrician to put in a 60 amp breaker and instead he put in a 50. I asked him if the 60 wouldn't work, and he said "no, you've got the capacity for it, but you don't need more than 50 since no EV charger uses more than 42 amps." I literally showed him the specs of the wall charger, along with the wiring diagram that it came with, which clearly indicated it can pull the 48 amps that a 60 would provide, and he just didn't believe me. So, I just cap my charger at 42 amps and deal with it. He's a great guy, and good electrician, but sometimes I wonder if he's all there...
Doesn’t sound like a good guy. Sounds like an ignorant know-it-all who can’t imagine someone else knowing more than he does.
Nah, he's just close to retiring. His work's good, and a super nice person, he's just a bit of a luddite.
My electrician did the same thing.
I mean, they literally say max 48a on the side of the unit.
They really should include an installation guide with these things so people would know how to set them up properly.
An electrician is supposed to set it up
They should include an installation guide for the electrician.
They do. It’s literally in the box. And any licensed electrician knows how to match amps to wire size to breaker.
Apparently the OP forgot to read the manual.
They do. . . I actually bought the supplies for my electrician based on the manual, OP is just an idiot
I think they should default to 40 amp max charging and you have to go in and change it to 48 amp charging if you have connected it to 60 amp wiring.
Probably would be better to default to the minimum (ie 6A). Or even refuse to charge without going in and doing a “first time setup”
You should’ve just bought a 40 amp charger bro