2026 NEC Motions Commitee Report Released 🔥

[brycenesbitt]

I learned a bunch of new things I didn't know last week thanks for the great lessons on my show last week sir!

It was fun hanging out with you on "High Voltage Podcast", thanks.

For 277V the reason to put effort into that is for Four-wire Wye Configuration 480V systems.
You can derive 277V easily. But presently to do charging you then need a transformer to net 240V and that's
a waste. The car can suck in the 277V without much of any trouble.

The issue is that Tesla released some vehicles that internally get cranky near 277V. If the power supply is a few percent
high, they shut down. What's unclear is if Tesla can adjust that threshold without a physical visit to the car, or parts replacement.

 

[retirede]

It was fun hanging out with you on "High Voltage Podcast", thanks.

For 277V the reason to put effort into that is for Four-wire Wye Configuration 480V systems.
You can derive 277V easily. But presently to do charging you then need a transformer to net 240V and that's
a waste. The car can suck in the 277V without much of any trouble.

The issue is that Tesla released some vehicles that internally get cranky near 277V. If the power supply is a few percent
high, they shut down. What's unclear is if Tesla can adjust that threshold without a physical visit to the car, or parts replacement.

The level 2 definition in the J1772 standard specifies 208 and 240 nominal voltages. In 2017, there was a proposal to define AC level 3 as 208-600V, but it was never adopted or implemented. Ford EVs will fault if the applied voltage exceeds 260V (it was originally 252, but was increased after encountering some exceeding that). Not sure about other makes.

 

[don_resqcapt19]

Yes.
In commercial we run L2 EVSE on 208V from a 120/208Y with no "neutral" to speak of.
With J3400 and some cooperation on voltage thresholds from Tesla, and we could have 277V Level 2 EVSE from heavy commercial transformers (and we could have had that with J1772 without much trouble also).

There's shockingly little that's special about EVSE, to justify all the lines of regulatory code applied to it.
It seems like code sections written to be all modern or whatever, rather than to solve an identifiable problem.

Why would anyone want single phase 277 for this when 3 phase 480 would be a better choice?

 

[brycenesbitt]

The level 2 definition in the J1772 standard specifies 208 and 240 nominal voltages. In 2017, there was a proposal to define AC level 3 as 208-600V, but it was never adopted or implemented. Ford EVs will fault if the applied voltage exceeds 260V (it was originally 252, but was increased after encountering some exceeding that). Not sure about other makes.

For Tesla, it's a model by model thing. Some vehicles are fine, some the threshold is too close to 277V -+ 5%.
Somewhere on this forum is a letter from Tesla on this topic.

The issue I see is how to handle J3400 to J1772 adapters when they plug into a 208-240V only vehicle. But overall I'm in favor of the hard work getting done to enable 277V for North American vehicles. In Europe they get to play with 3 phase L2 charging, but I don't see that coming to the US anytime soon given the lack of connector pins.

---
To be clear the vast majority of AC powered DC fast chargers take 3 phase 480.
The Level 2 discussion at 277 volts is limited to the onboard AC DC converter in vehicles, at the "home charger" or light commercial cost bracket.

 

[retirede]

For Tesla, it's a model by model thing. Some vehicles are fine, some the threshold is too close to 277V -+ 5%.
Somewhere on this forum is a letter from Tesla on this topic.

The issue I see is how to handle J3400 to J1772 adapters when they plug into a 208-240V only vehicle. But overall I'm in favor of the hard work getting done to enable 277V for North American vehicles. In Europe they get to play with 3 phase L2 charging, but I don't see that coming to the US anytime soon given the lack of connector pins.

---
To be clear the vast majority of AC powered DC fast chargers take 3 phase 480.
The Level 2 discussion at 277 volts is limited to the onboard AC DC converter in vehicles, at the "home charger" or light commercial cost bracket.

Totally agree. It’s just that there is currently no standard in place for 277V AC charging.

 

[brycenesbitt]

Totally agree. It’s just that there is currently no standard in place for 277V AC charging.

Here is an online thread about Tesla's on again off again support for 277V AC charging:

Info from Tesla - 277v feed to Wall Connector (HPWC) - Which Cars Support It

I have been involved in a number of threads on the forums regarding 277v support via the Wall Connector / HPWC. There seems to be a lack of clarity in what is and is not supported and whether it will require a trip to the service center to "reset" your car if the voltage is too high. Because...

teslamotorsclub.com

 

[Willie Snyder]

It was fun hanging out with you on "High Voltage Podcast", thanks.

For 277V the reason to put effort into that is for Four-wire Wye Configuration 480V systems.
You can derive 277V easily. But presently to do charging you then need a transformer to net 240V and that's
a waste. The car can suck in the 277V without much of any trouble.

The issue is that Tesla released some vehicles that internally get cranky near 277V. If the power supply is a few percent
high, they shut down. What's unclear is if Tesla can adjust that threshold without a physical visit to the car, or parts replacement.

The way I see it there are 4 important CAMs that either need to be rejected or we can just determine them to be a waste of ink as stated earlier in this thread:
625.4 There is no reason to add this reference to the language. I could be more qualified than you and you could be more qualified than me but this is constantly the MO from the CMPs pass it then we will see what it means.
625.43(E) What is the reason for this emergency shutoff requirement? How can it be realistically be implemented with hundreds of tenants in a multifamily dwelling?
625.44 Why does CMP-12 care what style connector is used for equipment connection and how is a non-locking style better than a J1772?
625.54 What is the substantiation to add the word "Outlets" in the language? This is all based on the substantiation to add 210.8(F) to the NEC without any technical merit to do so and it was rejected nationally when it was implemented to hardwired HVAC equipment and now EVSE manufacturers are standing up and calling BS! I will be watching with my popcorn and hoping the NEC gets back to a little bit of reality.