What adapter if I want to use a 40 amp breaker

[muddy-toe]

Garage/ work shop sub panel is fed by a 60 amp double pole breaker. Given I use my work shop I only want to put in a 40 or 30 amp breaker for charging. While Tesla shows that a 40 amp breaker charge rate is 30mph, there is no adapter assigned to a 40 amp breaker. A 30 amp double pole breaker is associated with NEMA 14-30 and charges at 22mph.
Is it the case that if you use a 50 amp or 40 amp dbl-pole breaker you simply use the NEMA 14-50 adapter? Note will only have a mobile adapter.

 

[Sophias_dad]

Yes, you'd want a 14-50 outlet and 40 or 50 amp GFCI breaker with appropriately sized wiring. The UMC is limited to 32 amps in any case, so you won't need to dial the amps down.

If at some point you get a Corded Mobile Connector it'll try to draw 40 amps, so don't do that.

 

[muddy-toe]

Thanks Sophia’s-dad. Did you mean “wall connector” as opposed to mobile connector in the last sentence?

 

[Freez]

The car will automatically set to the highest available amps of the equipment/power supply you have, and you can de-rate it from there. In this case, it will be 32AMPS, as that is the limit of the Mobile Connector. Tesla does sell a different type of connector called the “Corded Mobile Connector”. It looks the same as the Mobile Connector, but it has a 14-50 plug hardwired onto it, as opposed to the adapters you can use with the Mobile Connector. The benefit of the Corded Mobile Connector is that it can charge up to 40AMPS.

 

[strider]

Agree with the others. 40A breaker is limited to 32A continuous (80% of rated). You could use a 14-50 as the MC is limited to 32A anyway. Safest would be a 14-30 which would de-rate to 24A

 

[Watts_Up]

Garage/ work shop sub panel is fed by a 60 amp double pole breaker. Given I use my work shop I only want to put in a 40 or 30 amp breaker for charging. While Tesla shows that a 40 amp breaker charge rate is 30mph, there is no adapter assigned to a 40 amp breaker. A 30 amp double pole breaker is associated with NEMA 14-30 and charges at 22mph.
Is it the case that if you use a 50 amp or 40 amp dbl-pole breaker you simply use the NEMA 14-50 adapter? Note will only have a mobile adapter.

If you plan to have a permit to install an additional circuit breaker,
you should stay below 50% of the capacity of your panel or sub-panel, or 30A in your case.

Otherwise you would need to use an auto-switch able to detect any extra load which could
be running at any time, such as an HVAC, Dryer, or Oven range, to disconnect your EV to
avoid any overload, and start automatically after a delay when the extra load ends,
See for example the DCC-9 or DCC-10 power switch.

So in your case, you should use a 30 A circuit breaker, to charge you car under 80% or 24 A.
In the case of a 14-30 NEMA plug, you will also need to use a GFCI breaker,
unless you use a Tesla wall mounted charger which doesn't require using a CFCI breaker.

 

[muddy-toe]

I actually like the 30 amp breaker, with 14-30 adapter, I assume 21 mph charging is good enough for our around town daily needs.

 

[ATPMSD]

So let’s talk about wiring and usage. Since you have a 60-amp service to the garage consider wiring a 14-50 outlet with a 50-amp breaker and the appropriate wiring. This gives you the option of using that outlet in the shop, if you need it, and it leaves future options open.

If you use the Tesla Mobile Connector with the 14-50 adapter the car will draw no more than 32-amps as this is the limit of the connector. You can also now, or in the future, install a wall connector. The wall connector allows you to configure it as being on a 20, 30, 40, 50 or 60-amp circuit. So you could start with it configured as being on a 40-amp circuit and the car will charge at 32-amps. In the future you can easily change the setting to a 50-amp circuit and charge at 40-amps.

 

[Sophias_dad]

If you plan to have a permit to install an additional circuit breaker,
you should stay below 50% of the capacity of your panel or sub-panel, or 30A in your case.

I'd like to see a reference on this rule. I don't really believe it.

As 'proof' I have a fully permitted pool subpanel that runs off a 30 amp feed breaker and contains a 20 amp pool pump breaker and 10 amp pool light breaker. Last I checked, 20 was more than 50% of 30.

 

[Jerryr]

The car will automatically set to the highest available amps of the equipment/power supply you have, and you can de-rate it from there. In this case, it will be 32AMPS, as that is the limit of the Mobile Connector. Tesla does sell a different type of connector called the “Corded Mobile Connector”. It looks the same as the Mobile Connector, but it has a 14-50 plug hardwired onto it, as opposed to the adapters you can use with the Mobile Connector. The benefit of the Corded Mobile Connector is that it can charge up to 40AMPS.

It seems that the Corded Mobile Connector is discontinued by Tesla

 

[ATPMSD]

It seems that the Corded Mobile Connector is discontinued by Tesla

No, it is just out of stock

Corded Mobile Connector

The Corded Mobile Connector features a NEMA 14-50 plug and improved charging speeds in comparison to the Mobile Connector with NEMA 5-15 Adapter. Includes: 1x NEMA 14-50 Corded Mobile Connector - 20’ cable 1x storage bag Corded Mobile Connector Manual Note: The Corded Mobile Connector is...

shop.tesla.com

 

[Darmie]

If you already have a mobile connector and you are looking for an adapter, I would recommend a 14:30 and use a 4 pin dryer outlet as your receptacle. That will give you your 30 amp cap for you requirements. This way, you need not to worry about lowering the amperage draw on the vehicle screen. The adapter will communicate with the vehicle and auto set the vehicle to consume no more than that amperage.

Gen 2 NEMA Adapters

Use a variety of household outlets to charge your Tesla with a Gen 2 NEMA Adapter. Simply attach the appropriate adapter to your Mobile Connector, plug into the corresponding outlet and begin charging. Adapter Max Distance Gained Per Hour of Charge Model S Model 3 Model X Model Y 5-15 3...

shop.tesla.com

if you have a little money to spare, I would purchase a Tesla V-3 HPWC. You use your phone to connect to the unit and set it to what ever breaker you are using, 30 or 40. Then it will draw only 80pct of the breaker that is supplying the connector. If you go this route, ensure you log into the HPWC and properly configure to what breaker you are using for if not, it will draw the full 48 amps.

 

[21miDay]

I'm not sure what voltage you are talking about. You might want to look at this if you are working on 120 volts: TT-30 Adapter for Tesla Model S/X/3/Y Gen 2

This page is also helpful: CarCharging.us

 

[muddy-toe]

Yes, you'd want a 14-50 outlet and 40 or 50 amp GFCI breaker with appropriately sized wiring. The UMC is limited to 32 amps in any case, so you won't need to dial the amps down.

If at some point you get a Corded Mobile Connector it'll try to draw 40 amps, so don't do that.

Thanks all for the input. My garage/ wood shop already has a few 220 receptacles for 3hp shop saw, shaper, planer etc. obviously I never have more than one of those beasts on at a time, so now power issues there with the 60 amp panel. I anticipate having to ensure that I NEVER use my 220 machinery when charging the Tesla.
Given that, “IF” the mobile unit limits amperage draw to 32 amps with a 14-50 on a 50amp breaker then I am good to go. PS using #8 4 wire with 25’ run from sub planer.

 

[muddy-toe]

Thanks all for the input. My garage/ wood shop already has a few 220 receptacles for 3hp shop saw, shaper, planer etc. obviously I never have more than one of those beasts on at a time, so now power issues there with the 60 amp panel. I anticipate having to ensure that I NEVER use my 220 machinery when charging the Tesla.
Given that, “IF” the mobile unit limits amperage draw to 32 amps with a 14-50 on a 50amp breaker then I am good to go. PS using #8 4 wire with 25’ run from sub panel.

 

[ATPMSD]

I actually like the 30 amp breaker, with 14-30 adapter, I assume 21 mph charging is good enough for our around town daily needs.

My advice is to not plan for the minimum and instead install the maximum. BTW, that 21 miles figure assumes you consume power at the standard Tesla uses, most people consume more power per mile than the Tesla standard. Multiplying those figures by 75-80% will give you a better estimate.

 

[ATPMSD]

Given that, “IF” the mobile unit limits amperage draw to 32 amps with a 14-50 on a 50amp breaker then I am good to go. PS using #8 4 wire with 25’ run from sub planer.

Yes, the mobile connector will limit the charge rate to 32-amps. As to the wire size, it depends on the wire type

Cerrowire Resources - Ampacity Charts

Ampacity is the maximum current that a conductor can carry continuously under the conditions of use without exceeding its temperature rating. Cerrowire's ampacity chart helps calculate the load requirement for a circuit.

www.cerrowire.com

 

[Sophias_dad]

Thanks all for the input. My garage/ wood shop already has a few 220 receptacles for 3hp shop saw, shaper, planer etc. obviously I never have more than one of those beasts on at a time, so now power issues there with the 60 amp panel. I anticipate having to ensure that I NEVER use my 220 machinery when charging the Tesla.
Given that, “IF” the mobile unit limits amperage draw to 32 amps with a 14-50 on a 50amp breaker then I am good to go. PS using #8 4 wire with 25’ run from sub planer.

You should not rely on the 'next guy' to not plug in something that will draw 50 amps unless your wire/breaker is all capable of 50 amps. Either use a 40 amp breaker(and specifically label the 14-50 as '40 Amps') or use wire/breaker good for 50 amps. #8 is okay for 50 amps if its conductors-in-conduit, but only 40 amps if you are running NM-B(which isn't allowed to be exposed in a garage anymore, BTW).

And of course, don't get a crappy Leviton 14-50.

 

[Rocky_H]

My garage/ wood shop already has a few 220 receptacles for 3hp shop saw, shaper, planer etc.

Oh, well that's new info. Would you plan to use one of those existing ones, or do you want to put in a new one in a different location? Tesla does sell adapters for most common outlet types, so if there is already one in the right place, you could probably just use it.

 

[Watts_Up]

I'd like to see a reference on this rule. I don't really believe it.

As 'proof' I have a fully permitted pool subpanel that runs off a 30 amp feed breaker and contains a 20 amp pool pump breaker and 10 amp pool light breaker. Last I checked, 20 was more than 50% of 30.

Well, the NEC provides a set of rules and requirements which are often the subject of heavy discussions !!!
Such as for example the maximum number of 5-15 or 5-20 NEMA plugs that could be connected to the same circuit breaker...
I am not a certified electrician either, so I am only reporting talks I had with installers or comments that I found.

In the case of overloading, the NEC 430 has a 120% rule used as acceptable safety limit for overcurrent for busbar or conductors.
This can be used in particular in the case of initial motor current surge, and I think there is a 10 minutes limit or something like that.
Overload calculation is a very complex subject, such as determining the typical and maximum number of devices running at the same time.

Coming back to the 50% common rule of my posting, this was referring to a situation where you will have an EV charging all the night
using then 30 A of the 60 A total panel capacity. So there would be another 30 A available to other devices running sporadically.
If you consider the 120 % NEC rule, your panel could accept (60 A x 120%) = 72 A, or (72 A - 30 A) = 42 A for the other device.

But the possible second load of 42 A in this example could only apply to something like an HVAC running for 5 minutes every 15 minutes or so.
This is different of an EV charging were your constant load should not be larger than 80% of the line capacity since charging could last like 4 to 8 hours.

Don't take literally my comments, there are load specialists that you can consult, also permit inspectors have their own rules,
but this could give you an estimate recommendation preventing overloading your panel, or use an auto-switch otherwise.