Article 625 Electric Vehicle Power Transfer System

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Hello. I’m being tasked with potentially installing a Tesla Charging station in a residential garage. I’ve never done one but after reviewing the code it seems over current protection must be sized no less than 125% of the maximum load of the EV supply equipment. With that said, I know some of these have variable settings, like 25-45-90 amps. So would you hypothetically size for the max of 90 amps? Any direction or cautionary tales are more than welcome
I don’t have the cut sheet on which Tesla charger the customer wants installed either.
 
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You can size it for your maximum setting, if I'm not mistaken.

125% of maximum correct? I know there is venting requirements potentially based on system and location... just wondering if anyone has a good grasp as to what I’m walking into tomorrow.


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I meant your 25 or 45 amp setting options. Why have them otherwise?

Honestly Larry, I’ve no clue. I’ve never been in an EV and don’t plan on owning one. I’m sort of just trying to piece the requirements together this evening. Article 625.48 seems interesting. If used as optional standby, use art 702, when used as a power production source, 705 applies. Sounds like it’ll be a fun challenge for this apprentice


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retirede

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How fast does the customer want it to charge?
If you set the max output to 48, you need a 60A circuit; 40 and you need a 50, etc.
 
Location
Massachusetts
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Electrician
Honestly Larry, I’ve no clue. I’ve never been in an EV and don’t plan on owning one. I’m sort of just trying to piece the requirements together this evening. Article 625.48 seems interesting. If used as optional standby, use art 702, when used as a power production source, 705 applies. Sounds like it’ll be a fun challenge for this apprentice


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FYI, I see you comment often. Thanks for sharing your knowledge. You seem like the type who has forgotten more than I’ve learned. Thanks again though and please keep it up


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Location
Massachusetts
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Electrician
How fast does the customer want it to charge?
If you set the max output to 48, you need a 60A circuit; 40 and you need a 50, etc.

Honestly not sure. Boss called me this evening asking what I knew about EVs and said I had to meet a potential customer in the AM. All I know is it’s a Tesla charger, not sure which type or anything.


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wwhitney

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The current Tesla Wall Connector (3rd generation) maxes out at 48A continuous, so it needs at most a 60A circuit. That would be #6 Cu for a 75C wiring method, or #4 Cu for a 60C wiring method.

Older versions did support higher settings, so there's some chance that the customer has one of those. You'll need to clarify with the customer.

Cheers, Wayne
 
Location
Massachusetts
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Electrician
The current Tesla Wall Connector (3rd generation) maxes out at 48A continuous, so it needs at most a 60A circuit. That would be #6 Cu for a 75C wiring method, or #4 Cu for a 60C wiring method.

Older versions did support higher settings, so there's some chance that the customer has one of those. You'll need to clarify with the customer.

Cheers, Wayne

Thanks Wayne.
Do you happen to know if those require ventilation and if they’re listed for power production or optional standby? And power production basically means it has a GFCI on it?
Interesting read this Art 625


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wwhitney

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The stuff about ventilation in Art 625 is a hold over from systems that use lead acid batteries that can release hydrogen gas when charging/overcharged. It's not applicable to modern EVs.

The TWC wall connector has a J1772 connector that plugs into the car, and that connection standard includes some simple way for it to tell EVs "no ventilation provided." So if someone drove up a 20 year old EV with lead acid batteries and tried to charge, its controller should prevent it from charging.

I'm not sure what "power production" term you are referring to, I would think that refers to bidirectional power transfer. A still emerging technology, I don't think it's commercially available.

As to GFCI protection, the requirements depend on which year NEC you are subject to and perhaps which TIAs to that version your jurisdiction has adopted. I think that the latest versions of the NEC requires GFCI for any cord and plug protected EVSE, but not hardwired. Not sure, check the applicable to you version of Art 625.

Cheers, Wayne
 
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Location
Massachusetts
Occupation
Electrician
The stuff about ventilation in Art 625 is a hold over from system that use lead acid batteries that can release hydrogen gas when charging/overcharged. It's not applicable to modern EVs.

The TWC wall connector has a J1772 connector that plugs into the car, and that connection standard includes some simple way for it to tell EVs "no ventilation provided." So if someone drove up a 20 year old EV with lead acid batteries and tried to charge, its controller should prevent it from charging.

I'm not sure what "power production" term you are referring to, I would think that refers to bidirectional power transfer. A still emerging technology, I don't think it's commercially available.

As to GFCI protection, the requirements depend on which year NEC you are subject to and perhaps which TIAs to that version your jurisdiction has adopted. I think that the latest versions of the NEC required GFCI for any cord and plug protected EVSE, but not hardwired. Not sure, check the applicable to you version of Art 625.

Cheers, Wayne

Thank you Wayne. And yes, “bidirectional power feed” via 625.48 Interactive systems.
Hopefully I get to do this system. I’m getting excited


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retirede

Senior Member
Location
Illinois
The stuff about ventilation in Art 625 is a hold over from systems that use lead acid batteries that can release hydrogen gas when charging/overcharged. It's not applicable to modern EVs.

The TWC wall connector has a J1772 connector that plugs into the car, and that connection standard includes some simple way for it to tell EVs "no ventilation provided." So if someone drove up a 20 year old EV with lead acid batteries and tried to charge, its controller should prevent it from charging.

I'm not sure what "power production" term you are referring to, I would think that refers to bidirectional power transfer. A still emerging technology, I don't think it's commercially available.

As to GFCI protection, the requirements depend on which year NEC you are subject to and perhaps which TIAs to that version your jurisdiction has adopted. I think that the latest versions of the NEC requires GFCI for any cord and plug protected EVSE, but not hardwired. Not sure, check the applicable to you version of Art 625.

Cheers, Wayne

Tesla has a proprietary connector. Every other EV make uses the J1772, but not Tesla.
 

wwhitney

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Berkeley, CA
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Tesla has a proprietary connector. Every other EV make uses the J1772, but not Tesla.
Tesla uses a proprietary mechanical connector, but electrically they are the same, so the protocol for "ventilation required" and "ventilation available" will be the same (although I don't know the details of the protocol). There are mechanical converters between Tesla and standard J1772, each way.

But thank you, an important detail I omitted.

Cheers, Wayne
 
Location
Massachusetts
Occupation
Electrician
Tesla uses a proprietary mechanical connector, but electrically they are the same, so the protocol for "ventilation required" and "ventilation available" will be the same (although I don't know the details of the protocol). There are mechanical converters between Tesla and standard J1772, each way.

But thank you, an important detail I omitted.

Cheers, Wayne

Are they typically 4 wire branch circuits?


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Location
Massachusetts
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EVSEs are (almost) all 2-wire 240V loads. Some come with NEMA 14 plug on them, which necessitates running a 120/240V 3-wire circuit for the NEMA 14 receptacle. In all other cases, a 240V circuit suffices. I believe the Tesla Wall Connector is typically hard wired.

Cheers, Wayne

Interesting
I’ve been reading the Gen3 wall manual and they spec out 90c rated wire. So THHN, #6, which means it’s going to be EMT all the way to the panel. Or use MC and table 311.60. I see a neutral is referenced but in the literature they only show two phases and a ground being connected


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retirede

Senior Member
Location
Illinois
Tesla uses a proprietary mechanical connector, but electrically they are the same, so the protocol for "ventilation required" and "ventilation available" will be the same (although I don't know the details of the protocol). There are mechanical converters between Tesla and standard J1772, each way.

But thank you, an important detail I omitted.

Cheers, Wayne

That is correct - the communication protocol between the car and the EVSE is the same.
Some are reporting that Elon’s newest public EVSEs are smart enough to realize the car is not a Tesla and refuses the charge connection, rendering those adapters non-functional!
 
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