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40 amp maximum?

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Getting quotes for installing a Tesla Wall
connector. One of the electricians asked for photos of my panels before quoting and after looking said that I could only do a 40-amp breaker in my current panel.

I was hoping for a 50 or 60, but since that isn’t possible, should I still go with the Tesla Wall connector?

Was anyone else here limited to 40 amps for the install?
 
Getting quotes for installing a Tesla Wall
connector. One of the electricians asked for photos of my panels before quoting and after looking said that I could only do a 40-amp breaker in my current panel.

I was hoping for a 50 or 60, but since that isn’t possible, should I still go with the Tesla Wall connector?

Was anyone else here limited to 40 amps for the install?
I was limited to 50.

Problem with 40a breaker is there is no plug assigned to it. Your allowed to put a 14-50 but need to treat it as a 40a circuit. That means setting the charging to 32a in the car.

Safest way to do that is with a WC. You can set the 40a breaker setting in the WC.
 
Sure, why not? Everyone wants to put in "the fastest" one, but even though you are getting a LR AWD model 3 (based on your participation in the LR / AWD waiting room thread), that means you would be charging at 30 "miles per hour" rate instead of 44 Miles per hour rate (40amp circuit, 80% limit for continuous charging = 32 amp charging rate).

I have a 60amp circuit myself (48 amp used for charging, due to the 80% rule above.. 44 miles per hour) and I can tell you that there has not been a single time where the difference between 30 miles per hour and 43-44 miles per hour has been significant (or even noticeable, frankly).

Even in CA where we have punitive "time of use" electricity rates, where you basically HAVE to fit charging into the midnight to 6 am window for most people, thats a circumstance where it "might" matter, if one drives enough daily to not be able to fit charging into that window.

TL ; DR -- Pretty much any 240v charging is good, and 40amp is perfectly fine, although its not "the fastest it can go".
 
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Should not be a problem, you will still be able to get a full charge overnight. Just be sure to set the switches correctly in the wall connector for 32 amps (40 amp breaker should only have 80% continuous load so 32 amps max for the wall charger).
 
40a seems like an odd cutoff, someone else mentioned this in another "Getting a circuit/charger installed" thread.

Like @brkaus mentioned a 50a is a pretty standard spec, there's even two NEMA outlet specifications for 50a (N14-50 and N6-50). I realize you're talking a hardwired TWC (vs. a plugin type EVSE), but this is more about the circuit itself.

Personally, I'd ask why, it may be as simple as code requirement / existing circuits / max load / total service amperage, etc., but I'd just confirm it's not because of some misunderstanding of the EVSE and/or charging capability of the vehicle.

FWIW, I had a 50a circuit installed, and an N6-50 outlet in the garage, right next to the breaker box, then we use a plugin 40a EVSE.
 
40a seems like an odd cutoff, someone else mentioned this in another "Getting a circuit/charger installed" thread.
Why would that be odd? When you do a load calculation, it's going to show some number of amps still available that probably won't be some exact increment of 10. That could be 21 or 34 or 42 or something, so the size circuit you can still add is whatever is rounded down from that. If it was forty-something, then a 40A circuit is what you have leftover capacity to add--it doesn't relate to what outlet types there are.
 
Why would that be odd? When you do a load calculation, it's going to show some number of amps still available that probably won't be some exact increment of 10. That could be 21 or 34 or 42 or something, so the size circuit you can still add is whatever is rounded down from that. If it was forty-something, then a 40A circuit is what you have leftover capacity to add--it doesn't relate to what outlet types there are.

Odd because a few people have mentioned electricians doing a 40a vs. a 30a or a 50a, just seems like a pattern that's not being driven by an actual load calculation, but some kind of preconceived notion of the charging requirements for an EV.

I also shot pics of my breaker, and all 3 contractors said 50a was likely fine due to the space available, but they wouldn't make a final call without an onsite review - i.e., determining total load from a pic seems a little spurious.

But whatever, just something I noticed, and I stand by my recommendation of actually asking the contractor why it's limited to 40a.
 
I indeed got 40A service (50A breaker) on a 2019 install. It's plenty. That will charge you up at around 37 mph. I've honestly never had once instance where it really needed to be faster than that as far as the time it takes. Now if I could wave my magic wand and get 50 or 60 for the purposes of preheating the car on cold days. Yes, probably. But it's still not a big issue and 40A warms it up reasonably well.
 
I indeed got 40A service (50A breaker) on a 2019 install. It's plenty. That will charge you up at around 37 mph. I've honestly never had once instance where it really needed to be faster than that as far as the time it takes. Now if I could wave my magic wand and get 50 or 60 for the purposes of preheating the car on cold days. Yes, probably. But it's still not a big issue and 40A warms it up reasonably well.

Yeah, when you start looking at different rates, like @jjrandorin pointed out, then considering that over a multi-hour charging period, it's not a huge difference.

A 32a at 30 miles/hour vs. a 40a at 37 miles/hour, means about every 4.5 hours, the faster charger gains an hour of (equivalent to 32a) charging time - but an overnight charge of 8 hours mean either can put a full charge into a TM3 (assuming a 15-20 to 80-ish percent).

I don't think there's many short terms charging scenarios where the extra +7 miles/hour are going to make or break the situation.
 
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Personally, I'd ask why, it may be as simple as code requirement / existing circuits / max load / total service amperage, etc., but I'd just confirm it's not because of some misunderstanding of the EVSE and/or charging capability of the vehicle.

Well, my "main" panel is on the outside of the house, but on the opposite side of the house from the garage. The subpanel in the garage is full of 20amp breakers. They said they could install a 50 or 60, but it would require new wiring from that outdoor panel to the garage, and that triples the install charge.

I guess I'll just go with 40amps.
 
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'Full of 20 amp breakers' doesn't mean 'all these breakers have any significant load'. Did anyone do a real load calculation? Is the 'Main' panel just a big breaker, and the rest of the breakers are in the garage subpanel. What size breaker is feeding that garage subpanel?
 
'Full of 20 amp breakers' doesn't mean 'all these breakers have any significant load'. Did anyone do a real load calculation? Is the 'Main' panel just a big breaker, and the rest of the breakers are in the garage subpanel. What size breaker is feeding that garage subpanel?
Do these pics help?
 

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I've been charging my TWO EVs for years on the same 240v outlet. I don't even know how long it takes because I charge at night, and my cars are full in the morning.

What's with all the concern over how fast these other ways will charge? You just looking for ways to spend more money? You'll be asleep, for heaven's sake! You don't need anything more than the cord that came with the car, with the 240v adapter plugged into it, and a $15 outlet. And go to bed and quit worrying.
 
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I've been charging my TWO EVs for years on the same 240v outlet. I don't even know how long it takes because I charge at night, and my cars are full in the morning.
I'll agree to this part, because a 40A circuit is a very good charging speed and should generally be sufficient.
What's with all the concern over how fast these other ways will charge? You just looking for ways to spend more money? You'll be asleep, for heaven's sake! You don't need anything more than the cord that came with the car, with the 240v adapter plugged into it, and a $15 outlet. And go to bed and quit worrying.
But why do you continue to go all around these forums giving bad and incorrect advice?
Using the el-cheapo $15 Leviton outlet is terrible advice to give. The much more solid and safe ones are not very much more, for around $40-$50, so are a much better decision. And no, that is not all the cost. If doing the outlet, it does require to be code compliant that it uses a GFCI breaker. The economics of deciding to just use the included cord and an outlet have gotten a lot worse because of that NEC requirement now.
 
You just looking for ways to spend more money? You'll be asleep, for heaven's sake! You don't need anything more than the cord that came with the car, with the 240v adapter plugged into it, and a $15 outlet. And go to bed and quit worrying.

-I get local incentives from the utility that offset the extra cost of a Tesla Wall Connector.
-Not every electrician I've talked to has mentioned the 40 amp max. If I go with someone who doesn't recognize a possible limitation, I risk burning down my house. I was just asking to see what other had encountered.
-Check your tone.
 
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-I get local incentives from the utility that offset the extra cost of a Tesla Wall Connector.
-Not every electrician I've talked to has mentioned the 40 amp max. If I go with someone who doesn't recognize a possible limitation, I risk burning down my house. I was just asking to see what other had encountered.
-Check your tone.

Looking at your panels, I can easily see why an electrician would be hesitant to go more than 40 amps. That entire panel full of 20 amp breakers is only supplied by a 70 amp breaker.

If everything is right, even if you put in a 60 amp breaker(on your 70 amp panel!) and its too much load, the 70 amp breaker will trip and you'll know you've overstepped the limit. There should be no risk at all of burning down your house.

Notably, I see both a 240V dryer breaker in the main panel and a 120V dryer(gas) breaker in the subpanel. This implies that one(probably the 240V) is really unused, and you have at least 30 extra amps of capacity at the main panel(if needed).

On that subpanel there are two 'Furnace' breakers. I wonder what's up with that. I assume they are gas based and only have a fan motor to run.


Not actually looking at the faceplates of the various 120V loads off the subpanel, I could even see nuisance trips with an extra 40 amp breaker(32 amp load), since thats HALF the capacity of the entire panel. I don't even see a 'refrigerator' breaker, which I'm sure is there but unlabeled. Things like furnace, hydro tub, microwave, refrigerator, dishwasher all would have motors and heating elements and when run together might be concerning. If you are lucky they are on opposite legs of the 240V(or the electrician can swap them in seconds to make sure that's the case). Lets for a moment assume they are all on the same side, and take 10 amps each... that's 60 amps right there. In reality, most of them will only take 10 amps for a short period(seconds) during startup, so you are probably fine. And if you divide the loads properly, its 30 amps per leg of the 240, leaving a nice 40 for your charging needs.