2026 NEC Motions Commitee Report Released 🔥

Willie Snyder said:
I learned a bunch of new things I didn't know last week thanks for the great lessons on my show last week sir!
Click to expand...
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.
 
brycenesbitt said:
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.
Click to expand...
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.
 
brycenesbitt said:
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.
Click to expand...
Why would anyone want single phase 277 for this when 3 phase 480 would be a better choice?
 
retirede said:
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.
Click to expand...

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.
 
brycenesbitt said:
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.
Click to expand...
Totally agree. It’s just that there is currently no standard in place for 277V AC charging.
 
retirede said:
Totally agree. It’s just that there is currently no standard in place for 277V AC charging.
Click to expand...
Here is an online thread about Tesla's on again off again support for 277V AC charging:
teslamotorsclub.com

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 teslamotorsclub.com
 
brycenesbitt said:
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.
Click to expand...
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.
 
Willie Snyder said:
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.
Click to expand...
I will be on the floor in Las Vegas to argue for all four of those, plus Ryan Jackson's on listing for receptacles.
The strategy that's being talked about here is to pass the code as written, thus creating an emergency that needs to be fixed by TIA.
Ugh. How about just do it right the first time?
 
ramsy said:
Permits were never a physical barrier, but missing permits, and 2-pole Class-A GFCI, will weaponize underwriter's cause to deny claims.
Click to expand...
Everytime I see a post like this, I ask, How many times have you seen an insurer deny a claim because a home owner didn't get a permit or follow code? Everytime, I never get a response, or I get "well, never, but..."

Insurance is basically a protection against stupidity. Should insurance then not cover the idiot who put a propane heater under their diesel truck to get it started, then not only got the truck started on fire, but the garage it was in? Yes, it happened to a local guy, yes, insurance covered it.
 
A homeowner should never be prevented from doing their own work on their home, no matter what it is, as long as they follow the associated laws and requirements.

Why is an EV charger more special than someone installing their own service? The major issue seems to be around cheap 14-50 receptacles. Why not strengthen the UL listing around those?

Seems like if someone can do the work, and pass the inspection, that makes them a "qualified person" does it not?
 
ActionDave said:
That would expose the whole UL racket and bring attention to all the junk that they put their blessing on.
Click to expand...
Not sure where the issue is. The standard calls for the receptacle to carry its full load forever without excessive temperature rise. Something is causing this temperature rise, but not sure any real investigation has been done on why they are failing. Is it a problem with the receptacle, the plug on the cord, or with the installation of the receptacle?
 
It's a problem with the receptacle. Most of them get used at less than 50A and less than four hours. EV charging is the first application where they see max load for four or more hours. If there wasn't a problem with the receptacle why is there a new EV rated receptacle on the market with the same pin configuration?

Let's be honest, there is a whole lot of junk out there with UL stickers all over it. I'm not talking about counterfeit garbage, I'm talking about the "good stuff" from the official manufacturers.
 
don_resqcapt19 said:
Not sure where the issue is. The standard calls for the receptacle to carry its full load forever without excessive temperature rise. Something is causing this temperature rise, but not sure any real investigation has been done on why they are failing. Is it a problem with the receptacle, the plug on the cord, or with the installation of the receptacle?
Click to expand...
But UL doesn’t test them “forever.” I’m not familiar with the test procedure, but my guess is that they are tested at full rated current until the temperature stabilizes. I doubt the test adequately reflects real-world, long-term conditions.
The effects of long-term operation at elevated temps and after dozens (maybe hundreds) of insertion cycles are never observed in the lab.
 
ActionDave said:
If there wasn't a problem with the receptacle why is there a new EV rated receptacle on the market with the same pin configuration?
Click to expand...
The new Leviton EV receptacles I have in the van say CU only no aluminum wire allowed, also all hard wired terminations in chargers say CU wire only. The receptacles are just heating up and cooling down making AL expand and shrink loosening the screws.
 
pipe_bender said:
The new Leviton EV receptacles I have in the van say CU only no aluminum wire allowed, also all hard wired terminations in chargers say CU wire only. The receptacles are just heating up and cooling down making AL expand and shrink loosening the screws.
Click to expand...
There are plenty of 14-50R failures that were wired with copper.
 
retirede said:
There are plenty of 14-50R failures that were wired with copper.
Click to expand...
I have never seen such a failure, perhaps one DIY post on reddit where the charger was programmed for max ?
All the manufacturers investigated it and reproduced the problem, why else make such a unusual restriction?
 
retirede said:
But UL doesn’t test them “forever.” I’m not familiar with the test procedure, but my guess is that they are tested at full rated current until the temperature stabilizes. I doubt the test adequately reflects real-world, long-term conditions.
The effects of long-term operation at elevated temps and after dozens (maybe hundreds) of insertion cycles are never observed in the lab.
Click to expand...
The test continues at full load until 3 consecutive temperature readings 5 minutes apart so no change in temperature. I would expect that that does meet the real world as I doubt that there would be a knee point of 10 minutes where the temperature does not continue to rise.

As far as the insertion cycles, the temperature rise test is after 100 cycles of make and break at 150% of rated load.
However, I see I missed one item....the temperature test is done with DC and not AC.
 
Last edited:
don_resqcapt19 said:
The test continues at full load until 3 consecutive temperature readings 5 minutes apart so no change in temperature. I would expect that that does meet the real world as I doubt that there would be a knee point of 10 minutes where the temperature does not continue to rise.

As far as the insertion cycles, the temperature rise test is after 100 cycles of make and break at 150% of rated load.
However, I see I missed one item....the temperature test is done with DC and not AC.
Click to expand...
I wouldn’t expect DC vs AC to yield materially different results.
 
You must log in or register to reply here.
Top