It might not be. There is no reason for Tesla to have used a proprietary connector for the new UMC. It doesn't attach to their car. When I get my new UMC adapter (hopefully this week), I'll make an effort to find out if it can be sourced from a parts manufacturer.
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It might not be. There is no reason for Tesla to have used a proprietary connector for the new UMC. It doesn't attach to their car. When I get my new UMC adapter (hopefully this week), I'll make an effort to find out if it can be sourced from a parts manufacturer.
Plugsuvohio
Member
I have no details to review on any changes with the UMC, but it has to be pointed out that all sorts of things have changed in Article 625 of the national electric code. I've posted elsewhere on this if you search. Things including primary cord length (to the wall); what is defined as a mobile connector vs a stationary but relocatable one, vs fixed position and hard wired; and possible (I don't remember) that 32A would be the maximum amperage allowed on the cord connected primary. All of this has been in flux for at least the 3 years prior to the new 2017 standard and the previous versions even back to 2008. I suspect that Tesla has been dealing with their own solutions to the electrical codes in the US (and elsewhere); consumer desires, costs, etc on what is Level 2 general classed charging.
It is very confusing and the fact you can not read the published standards without purchasing them adds to the problem for nearly all of us out here. What you will find are proposed drafts of various versions and some records of public comment about NEC625; plus subsequent TIA (Temporary authorizations) to do something OTHER than the strict rule in the standard. Phew
stopcrazypp
Well-Known Member
But there is no standard for such a thing. I don't think anybody else even makes a UMC like Tesla's, where the adapters control the amperage the car draws.
It doesn't matter that there is no standard for attaching to a UMC. There are lots of connector manufacturers out there that make electrical connectors for various purposes. All the connector has to do is connect three 40A pins and two signal pins. I suspect Tesla could have sourced an electrical connector off the shelf for this. We'll see if that's the case...
stopcrazypp
Well-Known Member
Well for what it's worth, the European version was completely proprietary:
New UMC
They have to make the molds to have the tesla branding on it anyway (and probably to fit the resistor in), so I don't see why they would want to look for an off the shelf version.
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FlatSix911
Porsche 918 Hybrid
Correct. However, you can use the HPWC for the Model 3 to charge at 40A.
ccutrer
Active Member
If you have 40A wire, you should have a 40A breaker. I know you're stating the same thing, it's just all in the direction you're working the equation. The rules are that the breaker cannot exceed the rating of the wire, and the wire (and the breaker) must be 125% of a continuous load (or conversely, a continuous load is 80% of the wire/breaker rating). Then there's the exceptions - the breaker can be oversized by one standard size if there isn't a standard size available (thus why you can put a 60A breaker on 6awg NM, which is technically only good to 55A), but when basing continuous loads factors, you take the wire ampacity in such a situation (I.e. 6awg NM is only good to 44A continuous calculated load, even though you would put it on a 60A breaker). And then the exception that's relevant here - an outlet can be one sized up if there is not a standard outlet at the desired ampacity. I.e. if you have a 40A load (32A continuous) you're allowed to use a 14-50 or 6-50 outlet on a 40A wire with a 40A circuit, because there's no such thing as a 40A outlet. This is fairly common with ranges and ovens, and is part of the reason the Canadian 14-50 adapter limits to 40A/32A continuous. Whenever I use a 50A outlet, I always check the breaker (and if possible, the actual wire) to see if it's 40A or 50A, and use my US or Canadian 14-50 adapter as appropriate.
One final note - it's okay for the device connected to an outlet to draw less than the outlet is rated for. For example, I have 6awg wire run to an outlet in my garage, which is good to 65A (with 75° rated terminals), but the only EVSE I had at the time for my Leaf is a 16A (continuous) with a 10-30 connector. So to be legal, I put a 10-30 outlet on, with a 30A breaker (it's okay that the wire ampacity greatly exceed the breaker rating - just means my voltage drop was minimal). But doing my load calc to determine how much I could pull on my other garage circuit for charging our Tesla, I only took the 16A of the actual device connected to the outlet into account. This is essentially the new UMC will be in when plugged into a 14-50 on a 50A circuit - just drawing less than available. (To finish the story, when I got the leaf I downgraded the Tesla to a 40A breaker, so that 32 + 16 = 48, the amount of load I had available for the whole house. Then I finally got two Tesla wall connectors that are load sharing, so I switched to two 60A breakers, and either one is allowed to pull 48A, but the sum of the two is not allowed to be greater than 48A. It means my Leaf charges almost twice as fast because it's actually unusual that both vehicles are charging at the same time).
eladts
Member
If there is indeed the case, it is probably because there are a lot of 14-50 and 6-50 out there on 40A circuits where 40A charging is not safe. There should have been 14-40 and 6-40 to avoid this mess, but it is too late now. I suspect the new UMC will be shipping with Model S/X as well in the near future and the current UMC, as well of the CMC, will be discontinued. The Model S/X UMC is already out of stock, so if you want 40A pluggable ESVE you should buy the CMC before it is too late.
diamond.g
Active Member
Just an update, I ordered some of the adapters. They should be here on Monday, will post pics when I get them.
diamond.g
Active Member
Nope. Ended up emailing the accessories team. They gave me the tracking numbers. One for each adapter
What email address did you use? I placed an order a while ago and while I have been charged I haven't received anything and haven't gotten any response to my emails.
diamond.g
Active Member
So the new adapter is much more robust that the old ones found on existing UMCs. The high current pins are significantly larger than the old ones, which would reduce resistance heating. There are two dummy pins for tighter alignment. The ground pin is about the same size. And there is an extra signal pin (the old adapter had just one signal pin, this one has two). It appears the new adapters use a difference mechanism to tell the Mobile Connector what kind of plug it is connected to. The old UMC used a single signal pin with a specific resistor value connected to ground to identify charging amps. The new adapter does not use resistance to ground (infinite resistance to ground on either signal pin). And there isn't a consistent resistance measurement between the pins if I use a modern electronic ohm meter versus an old school analog meter. I suspect the two pins are connected to a chip of some sort for more complex information exchange (like maybe temperature).
So, the new adapters are even more complicated than I had thought. On a hunch, I cut the adapter cord and took a look inside. There are three beefy current conductors, and FOUR signal wires. Huh. So my guess is that the molded NEMA plug itself has a temperature sensor and who knows what else. Since there are only two signal wires leaving the adapter towards the MC, my suspicion above is probably correct in that there is probably some electronics that encodes a bunch of information for the MC onto those two signal wires.
I wonder if these new adapters are going to make it difficult or even impossible to easily create other adapters like for a TT-30. We'll have to wait and see whenever someone gets their hands on a new Mobile Connector...
I wonder if these new adapters are going to make it difficult or even impossible to easily create other adapters like for a TT-30. We'll have to wait and see whenever someone gets their hands on a new Mobile Connector...
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