Updating Outlet Charging Question

[KyleM3]

Hello. I’m trying to get my ducks in a row before placing my payment to get the vehicle production started. I’ve had 4 electricians come out and survey the covered parking and 3/4 decided the smartest, least headache route would be tapping into the main (rental apartment) and running the wires to a new outlet behind where the car would be parked.

With that being said, the education I’ve gotten from the forums and Reddit is that switching to a NEMA 14-50 is the easiest route. That, with 30-50 amp wiring (I hope I’m saying that correctly) should get me between 20-40 MPH on the charge. Is that right? I know I’d just need the $35~ 14-50 adaptor for the standard charging cord?

I ask because one electrician in particular kept pushing that I needed the Tesla wall charger to get maximum output. I’ve never gotten that impression, even from a Tesla Advisor himself, but because I’m new to Tesla and certainly not an electrician it made me skeptical. I always just thought that was a “pretty” way of charging and good for cord management. If I avoided the wall charger, what’s my maximum range realistically per hour? If it’s 17 or above, I’m good with that (considering the extra $635 for the charger is steep and in-and-out of stock).

All in all, if anyone experienced with the setup I’m shooting for could chime in I’d greatly appreciate it. I’m just looking for the most efficient way to charge without breaking the bank. The guy who quoted me the best price hasn’t installed Tesla chargers, but has installed the Juice Box ones.

 

[ucmndd]

A NEMA 14-50 outlet using the mobile connector that comes with the car (and the 14-50 adapter which you'll have to buy, yes) will charge at 32 amps and yield you somewhere between 25-30 miles per hour of range.

IF you are purchasing a long range Model 3 AND a wall connector AND install the wall connector on a 60 amp breaker, your car will charge at 48 amps and yield somewhere between 38-44 miles per hour of range. If you're buying a SR/SR+ the car's onboard charger is limited to 32 amps, so you'll realize no speed benefit at all from the wall connector.

Go with the 14-50.

 

[KyleM3]

A NEMA 14-50 outlet using the mobile connector that comes with the car (and the 14-50 adapter which you'll have to buy, yes) will charge at 32 amps and yield you somewhere between 25-30 miles per hour of range.

IF you are purchasing a long range Model 3 AND a wall connector AND install the wall connector on a 60 amp breaker, your car will charge at 48 amps and yield somewhere between 38-44 miles per hour of range. If you're buying a SR/SR+ the car's onboard charger is limited to 32 amps, so you'll realize no speed benefit at all from the wall connector.

Go with the 14-50.

The exact, straight forward answer I was looking for. I will be going long range, but there’s no added value to me for 30+ miles per charge. We don’t take long road trips and my work commute isn’t far. Thank you so much!

 

[SilverString]

A wall charger is nice but you don't need it, it is a convenience only in that it allows 30% faster charging and lets you keep the mobile charger in your car. If that is not of value to you then don't do it, it not going to change your overall experience with the car.

Do make sure you have the correctly sized wire for the 14-50 outlet and if you have the choice use 50 amp wiring with a 40 amp breaker and charge at 32 amps.

 

[ucmndd]

Do make sure you have the correctly sized wire for the 14-50 outlet and if you have the choice use 50 amp wiring with a 40 amp breaker and charge at 32 amps.

I would never purposely downrate a breaker on a general purpose accessible outlet like this. Code allows it for 50 amp receptacles (because there are no 40 amp receptacles), but it's generally intended for fixed installations of things like induction ranges, etc.

50 amp wiring, 50 amp receptacle, 50 amp breaker.

 

[user212_nr]

One issue that you will have with the mobile connector / 14-50 is that you will need to plug and unplug it each time you charge (or risk it being stolen).

There was a whole thread on this somewhere, but you could mount some kind of a box to the wall to put the connector in.

https://www.amazon.com/BUD-Industries-JBH-4958-KO-Knockout-Hinged/dp/B005UPA01Y

(lock not included).

I don't see any good deals on J1772 chargers that mount to the wall, but even that would be better than just the outlet.

 

[SilverString]

I would never purposely downrate a breaker on a general purpose accessible outlet like this. Code allows it for 50 amp receptacles (because there are no 40 amp receptacles), but it's generally intended for fixed installations of things like induction ranges, etc.

50 amp wiring, 50 amp receptacle, 50 amp breaker.

It's a matter of choice. Tesla recommends a 40.

 

[ucmndd]

It's a matter of choice. Tesla recommends a 40.

No, it’s a matter of doing things the right way.

50 amp receptacles are designed to draw... you guessed it, up to 50 amps. Putting a 50 amp receptacle in an accessible place for general use and then protecting it with a 40 amp breaker offers no extra protection or safety and dramatically increases the opportunity for nuisance trips and other problems. A 50 amp receptacle with 50 amp rated wiring should have a 50 amp breaker.

Where does Tesla recommend a 40 amp breaker on a 50 amp receptacle? Says 50 amp pretty clearly right here:

Mobile Connector

and here:

https://www.tesla.com/sites/default/files/pdfs/installation-guides/nema-14-50-installation-guide.pdf

 

[SilverString]

No, it’s a matter of doing things the right way.

50 amp receptacles are designed to draw... you guessed it, up to 50 amps. Putting a 50 amp receptacle in an accessible place for general use and then protecting it with a 40 amp breaker offers no extra protection or safety and dramatically increases the opportunity for nuisance trips and other problems. A 50 amp receptacle with 50 amp rated wiring should have a 50 amp breaker.

Where does Tesla recommend a 40 amp breaker on a 50 amp receptacle? Says 50 amp pretty clearly right here:

Mobile Connector

and here:

https://www.tesla.com/sites/default/files/pdfs/installation-guides/nema-14-50-installation-guide.pdf

I can't imagine why Tesla would recommend that, they have never been wrong before. ;-)

But 14-50 outlets are definitely NOT designed for a continuous duty cycle of 50 amps, that is a peak rating. Nor are they designed for a continuous duty of 40 amps, they are designed for a 32 amp maximum. Take a look at the the Tesla 14-50 adapter itself and you will clearly see a 250V 30A rating or about 7500 watts, most of us in the US run it at 240v 32A or 7680 watts. That is as high as any 14-50 outlet generally supplies. This is evidenced by the fact that the now defunct 14-50 HPWC maxed out at 32 amps. Why? Because you cannot safely draw more from a 14-50 outlet for more than short periods of time. More than 32 amps at 240v is almost always hard wired. Stoves, furnaces, etc.

Keeping that in mind you want to size your breaker accordingly because they also are not designed for a continuous duty cycle of their stated rating, which is also expressed as a peak current rating - on a 50 amp breaker 50 amps is when the breaker will trip. You say you want things to match? Then you use an 80% tolerance for continuous duty safety -ask any electrician. Last time I checked 80% of 40 was 32.

If you use a 50 amp breaker then you allow a 40 amp 8800 watt continuous draw on an outlet/plug combination that is designed for 7500 watts or 30 to 32 amps. Also if you are "nuisance" popping a 40 amp breaker and decide to just replace it with a 50, you are asking for trouble because a 40 amp breaker will not trip under normal use of a 14-50 outlet - Tesla mobile charger included.

When you buy a 2x4 at Home Depot is it actually 2 inches by 4 inches? Do you measure for length based on 2x4 inches? Electrical is the same.

I said it was a matter of choice because either will work 99% of the time with no problem, but you are giving bad advice.

 

[KyleM3]

I can't imagine why Tesla would recommend that, they have never been wrong before. ;-)

But 14-50 outlets are definitely NOT designed for a continuous duty cycle of 50 amps, that is a peak rating. Nor are they designed for a continuous duty of 40 amps, they are designed for a 32 amp maximum. Take a look at the the Tesla 14-50 adapter itself and you will clearly see a 250V 30A rating or about 7500 watts, most of us in the US run it at 240v 32A or 7680 watts. That is as high as any 14-50 outlet generally supplies. This is evidenced by the fact that the now defunct 14-50 HPWC maxed out at 32 amps. Why? Because you cannot safely draw more from a 14-50 outlet for more than short periods of time. More than 32 amps at 240v is almost always hard wired. Stoves, furnaces, etc.

Keeping that in mind you want to size your breaker accordingly because they also are not designed for a continuous duty cycle of their stated rating, which is also expressed as a peak current rating - on a 50 amp breaker 50 amps is when the breaker will trip. You say you want things to match? Then you use an 80% tolerance for continuous duty safety -ask any electrician. Last time I checked 80% of 40 was 32.

If you use a 50 amp breaker then you allow a 40 amp 8800 watt continuous draw on an outlet/plug combination that is designed for 7500 watts or 30 to 32 amps. Also if you are "nuisance" popping a 40 amp breaker and decide to just replace it with a 50, you are asking for trouble because a 40 amp breaker will not trip under normal use of a 14-50 outlet - Tesla mobile charger included.

When you buy a 2x4 at Home Depot is it actually 2 inches by 4 inches? Do you measure for length based on 2x4 inches? Electrical is the same.

I said it was a matter of choice because either will work 99% of the time with no problem, but you are giving bad advice.

Your original response was following what the electrician said. I wasn’t going 50 AMP regardless.

 

[MXLRplus]

Hello. I’m trying to get my ducks in a row before placing my payment to get the vehicle production started. I’ve had 4 electricians come out and survey the covered parking and 3/4 decided the smartest, least headache route would be tapping into the main (rental apartment) and running the wires to a new outlet behind where the car would be parked.

With that being said, the education I’ve gotten from the forums and Reddit is that switching to a NEMA 14-50 is the easiest route. That, with 30-50 amp wiring (I hope I’m saying that correctly) should get me between 20-40 MPH on the charge. Is that right? I know I’d just need the $35~ 14-50 adaptor for the standard charging cord?

I ask because one electrician in particular kept pushing that I needed the Tesla wall charger to get maximum output. I’ve never gotten that impression, even from a Tesla Advisor himself, but because I’m new to Tesla and certainly not an electrician it made me skeptical. I always just thought that was a “pretty” way of charging and good for cord management. If I avoided the wall charger, what’s my maximum range realistically per hour? If it’s 17 or above, I’m good with that (considering the extra $635 for the charger is steep and in-and-out of stock).

All in all, if anyone experienced with the setup I’m shooting for could chime in I’d greatly appreciate it. I’m just looking for the most efficient way to charge without breaking the bank. The guy who quoted me the best price hasn’t installed Tesla chargers, but has installed the Juice Box ones.

The included UMC (portable connector) is 32 amps max.

The fastest charging for a new Tesla is 48 amps. Technically this is higher than the continuous duty rating of a 14-50 and requires a HPWC.

If you hardwire it, you can pull 48 amps (11kW) using a 60 amp breaker and wiring.

But I'm a fan of the 14-50. 32/40 amps is fine for most people.

 

[smatthew]

I can't imagine why Tesla would recommend that, they have never been wrong before. ;-)

But 14-50 outlets are definitely NOT designed for a continuous duty cycle of 50 amps, that is a peak rating. Nor are they designed for a continuous duty of 40 amps, they are designed for a 32 amp maximum. Take a look at the the Tesla 14-50 adapter itself and you will clearly see a 250V 30A rating or about 7500 watts, most of us in the US run it at 240v 32A or 7680 watts. That is as high as any 14-50 outlet generally supplies. This is evidenced by the fact that the now defunct 14-50 HPWC maxed out at 32 amps. Why? Because you cannot safely draw more from a 14-50 outlet for more than short periods of time. More than 32 amps at 240v is almost always hard wired. Stoves, furnaces, etc.

Keeping that in mind you want to size your breaker accordingly because they also are not designed for a continuous duty cycle of their stated rating, which is also expressed as a peak current rating - on a 50 amp breaker 50 amps is when the breaker will trip. You say you want things to match? Then you use an 80% tolerance for continuous duty safety -ask any electrician. Last time I checked 80% of 40 was 32.

If you use a 50 amp breaker then you allow a 40 amp 8800 watt continuous draw on an outlet/plug combination that is designed for 7500 watts or 30 to 32 amps. Also if you are "nuisance" popping a 40 amp breaker and decide to just replace it with a 50, you are asking for trouble because a 40 amp breaker will not trip under normal use of a 14-50 outlet - Tesla mobile charger included.

When you buy a 2x4 at Home Depot is it actually 2 inches by 4 inches? Do you measure for length based on 2x4 inches? Electrical is the same.

I said it was a matter of choice because either will work 99% of the time with no problem, but you are giving bad advice.

Folks, please disregard SilverString's post. It's completely false.

A 14-50 outlet is rated for 50 Amps (40 continuous). Just because the Universal Mobile Connector doesn't use the full rating, doesn't mean that's how the outlet works.

It is legal to use a 40 amp OR 50 amp breakers on a 14-50 outlet, depending on the wire gauge you installed.

And you're completely wrong about the 14-50 HPWC.
“A Tesla 14-50 Wall Connector is your best charging solution with an existing NEMA 14-50 outlet. Offering a 25 percent faster charge compared to the Gen 2 Mobile Connector, the 14-50 Wall Connector is easy to use and convenient to install around your home or office.”
“Provides 40 amps (9.6kW) of power for all Model S, Model X and Model 3 Long Range vehicles. Model 3 Mid Range and Standard Range vehicles will charge at 32 amps when using the 14-50 Wall Connector.”

 

[ucmndd]

Nor are they designed for a continuous duty of 40 amps, they are designed for a 32 amp maximum. Take a look at the the Tesla 14-50 adapter itself and you will clearly see a 250V 30A rating or about 7500 watts, most of us in the US run it at 240v 32A or 7680 watts. That is as high as any 14-50 outlet generally supplies. This is evidenced by the fact that the now defunct 14-50 HPWC maxed out at 32 amps. Why? Because you cannot safely draw more from a 14-50 outlet for more than short periods of time. More than 32 amps at 240v is almost always hard wired. Stoves, furnaces, etc. .

This is quite simply factually wrong. All of it.

The “now defunct” 14-50 wall connector maxed out at 40 amps, which is 80% of 50, which is the max continuous load safe and allowable on a 50 amp outlet.

My gen 1 Tesla UMC supplies 40 amps to the car as well, again from a 50 amp outlet that is designed and expected by code to safely provide 80% of its amperage rating in a continuous load.

The fact Tesla cheaped out on the gen 2 UMC and it only draws 32 amps max is fully irrelevant.

The information you’re providing others is spectacularly wrong.

Also my question was real - where does Tesla recommend a 40 amp breaker?

 

[Rocky_H]

WOOOWWW! I wish I could dump more disagrees on that, because every single thing in @SilverString 's comment is completely wrong.

 

[pb2000]

Depending on your run length, it may be cheaper to go with a 6-50 so you don't need the neutral.

 

[sightman]

Depending on your run length, it may be cheaper to go with a 6-50 so you don't need the neutral.

I went with the 6-50. Even on the 14-50 adapter the UMC does not need a neutral, but a 14-50 outlet requires a neutral per code. So I went 6-50, no neutral exists on 6-50.

 

[SilverString]

Folks, please disregard SilverString's post. It's completely false.

A 14-50 outlet is rated for 50 Amps (40 continuous). Just because the Universal Mobile Connector doesn't use the full rating, doesn't mean that's how the outlet works.

It is legal to use a 40 amp OR 50 amp breakers on a 14-50 outlet, depending on the wire gauge you installed.

And you're completely wrong about the 14-50 HPWC.
“A Tesla 14-50 Wall Connector is your best charging solution with an existing NEMA 14-50 outlet. Offering a 25 percent faster charge compared to the Gen 2 Mobile Connector, the 14-50 Wall Connector is easy to use and convenient to install around your home or office.”
“Provides 40 amps (9.6kW) of power for all Model S, Model X and Model 3 Long Range vehicles. Model 3 Mid Range and Standard Range vehicles will charge at 32 amps when using the 14-50 Wall Connector.”

Hey dude that was not my post. Peace.

 

[SilverString]

WOOOWWW! I wish I could dump more disagrees on that, because every single thing in @SilverString 's comment is completely wrong.

No its not wrong Rocky it is a difference of opinion. Geez try to help you get attacked I thought you were a reasonable person.

No more post regarding electrical for me... I guess my 40 years of experience means nothing.

 

[smatthew]

Hey dude that was not my post. Peace.

huh? How was that not your post?

 

[ucmndd]

No its not wrong Rocky it is a difference of opinion.

This isn’t opinion. Nearly everything you said is factually wrong. Here. I’ll show you.

But 14-50 outlets are definitely NOT designed for a continuous duty cycle of 50 amps, that is a peak rating.

This is actually correct.

Nor are they designed for a continuous duty of 40 amps, they are designed for a 32 amp maximum.

This is factually wrong. Just plain false. NEC is quite clear that continuous loads are not to exceed 80% of the circuit rating. In this case, that’s 40 amps.

Take a look at the the Tesla 14-50 adapter itself and you will clearly see a 250V 30A rating or about 7500 watts, most of us in the US run it at 240v 32A or 7680 watts. That is as high as any 14-50 outlet generally supplies.

This is factually wrong.

This is evidenced by the fact that the now defunct 14-50 HPWC maxed out at 32 amps.

This is factually wrong.

Why? Because you cannot safely draw more from a 14-50 outlet for more than short periods of time.

This is factually wrong.

More than 32 amps at 240v is almost always hard wired. Stoves, furnaces, etc.

This is factually wrong. The NEMA 50 amp receptacles (14-50, 6-50) exist for the explicit purpose of providing non-hardwired 240v service up to 50 amps (40 amps continuous).

Keeping that in mind you want to size your breaker accordingly because they also are not designed for a continuous duty cycle of their stated rating, which is also expressed as a peak current rating - on a 50 amp breaker 50 amps is when the breaker will trip. You say you want things to match? Then you use an 80% tolerance for continuous duty safety -ask any electrician. Last time I checked 80% of 40 was 32.

This is factually wrong. I’m honestly having a hard time following your supposed logic here but I think you’re de-rating by 80% from 50 amps twice? Lol, why?

If you use a 50 amp breaker then you allow a 40 amp 8800 watt continuous draw on an outlet/plug combination

40 amps at 240v is 9.6kw, not 8.8, but yes, that’s exactly the idea.

that is designed for 7500 watts or 30 to 32 amps.

This is factually wrong. 50 amp receptacles are not designed for 30-32 amps.

Also if you are "nuisance" popping a 40 amp breaker and decide to just replace it with a 50, you are asking for trouble because a 40 amp breaker will not trip under normal use of a 14-50 outlet - Tesla mobile charger included.

This is factually wrong. A 40 amp breaker will trip if a 50 amp circuit draws more than 40 amps, which they’re supposed to be allowed to do, on account of being, you know, 50 amp circuits. This is why you size breakers to match the capacity of the circuit, not lower than what equipment with that plug is designed to expect.

When you buy a 2x4 at Home Depot is it actually 2 inches by 4 inches? Do you measure for length based on 2x4 inches? Electrical is the same.

I’ll give this a pass on being “factually wrong” despite being nonsensical.

I said it was a matter of choice because either will work 99% of the time with no problem, but you are giving bad advice.

It’s never bad advice to tell people to follow code and install something the right way, where 50 amps can be supplied as expected from a 50 amp plug.