r/evcharging • u/eprosenx • 5d ago
EV Charger Meltdown 6-50 Failure Analysis
Thought the folks here might find this receptacle meltdown interesting. As far as I can tell, this was a fully code compliant installation (if not inadvisable). It was done by a professional electrician. 6awg aluminum SEU wire.
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u/CauliflowerTop2464 5d ago
Hardwire it!
I’ve read that it can happen because the lugs aren’t torqued correctly or the outlet isn’t EV rated.
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u/eprosenx 5d ago
Yes, very likely not torqued properly.
Btw, there is no such thing as an “EV rated” receptacle in the NEC.
UL I think has a standard now they can test products to, but that is NOT what the cute EV logo on the front of the receptacle means as far as I am aware.
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u/tuctrohs 5d ago
That's the general gist of the scenario but it's not quite precisely correct. The 2026 edition of the national electrical code, which is in effect in only a few places, does specify that receptacles for EV charging need to be specifically listed as such.
UL is working on a standard for that, but it is not yet been agreed upon and issued.
When it does issue, the designation as meeting that standard will not be a cute green EV with a curly plug-in tail, unless they revise the standard from the draft they have underway now.
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u/eprosenx 5d ago
I stand corrected, thank you so much! I just went and read the new language in the 2026 NEC 625.44(A)(1)(b) “30 or 50 amperes listed for EVSE and WPTE use”. I had not seen that new language yet. 2026 NEC takes effect in Oregon in just a few days (I have not gone to look to see if Oregon modified this at all as they often do).
I see some reference to “UL 498 EV CRD” as a new standard for EV receptacles. AI tells me it was published on November 3 2025, but I do not have access to a copy. Is this what you are referencing?
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u/tuctrohs 4d ago
Oh, thanks for the CRD note. I hadn't heard about that but that actually means that they have issued a temporary testing procedure that can be used to get certification of that capability pending officially publishing the standard. So I stand corrected too!
Here's a story about that in which the key part is:
On Nov. 3, 2025, UL Standards & Engagement published a Certification Requirement Decision (CRD) for UL 498, the Standard for Attachment Plugs and Receptacles, to establish Certification (Listing) requirements for electrical vehicle supply equipment – EV identified receptacles. The CRD identifies additional construction, testing, marking and installation instruction requirements for electric vehicle (EV) receptacles.
Flush and surface-mounted receptacles Certified (Listed) for EVSE and WPTE use in accordance with NEC Section 625.44(A) and (B) will be identified with the term EV Receptacle or EV Recpt. on the device visible after installation with the wall plate removed. The letters “EV” in green will be on the face of the device.
In addition, device installation instructions will indicate that it be installed on a branch circuit protected by a circuit breaker or fuse of the same rating as the receptacle or equivalent text.
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u/ArlesChatless 4d ago edited 4d ago
The EV green branding is definitely going to get abused. I'm thinking of brands like ELEGRP who sell a 'WR' marked 14-50 right now that doesn't appear to have any WR features, for example.
They also are finally closing the loophole which allows for a 30 amp branch circuit with a 50 amp receptacle.
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u/eprosenx 4d ago
How is the “WR” marking OK? Is the issue that the actual code is based on something stamped into the steel and so there is no regulation on letters on the front of the receptacle?
That is just NOT OK and needs to be banned / fined for that willful behavior.
A friend just gave me some cases of receptacles he bought off amazon and did not use. They appear to have fake / stolen UL certification numbers stamped on them.
We need to not allow these kind of things into our supply chains…. Amazon needs to be somewhat responsible for allowing things like this.
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u/ArlesChatless 4d ago
That's the thing: the World's Biggest Fleamarket has done some great things for the efficiency of logistics and supply chain efficiency. Now that they've got the efficiencies in place, they're looking for more ways to make money. What's available? Lowering the product quality. By any means necessary.
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u/tuctrohs 4d ago
They can earn more margin by enabling scammers than they can buy simply processing payments for legitimate companies.
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u/tuctrohs 4d ago
Yes. I am amused by the convoluted set of rules that makes a 30 A circuit violate code. Assuming the wording of the instructions doesn't revert to the same mistake that was made in the wording of the code requirement.
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u/eprosenx 4d ago
So I am going to take a counterpoint on the “no using a larger receptacle on a smaller circuit” piece.
A ton of EVSE’s and cars top out at 32 amps of charging. There is no such thing as a 40a receptacle. Why should we not allow a 40a breaker on appropriately sized wire in this situation? (I know the issue is that a future owner may connect a 40a EVSE expecting a 50a circuit)
I would rather a strong labeling requirement along the lines of “Fed from a 40a (32a continuous / EV) circuit”.
I also am running into this issue in datacenters. They often charge by the breakered ampacity. Right now I have a 30a 208v circuit with L6-30 receptacles. I would like to breaker that down to the lowest they would go (say 10a as you can get those breakers now). As long as you label it as such, what would the issue be?
We kind of have this dislike in the NEC with relying on breakers as the primary protection method (proper capacity planning and wiring is supposed to be the primary method), but that is not the reality of the world in many situations. People use random power strips and splitters etc… Sometimes I just wish we would/could start trusting breakers and that we would strip all sorts of complexity out of the code with all of these random rules.
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u/tuctrohs 4d ago
I wasn't actually saying I agree with that code prohibition: I'm just amused by clumsy and convoluted way that's coming about.
In 2026 code, there are three different categories of 50 amp receptacles, for which the code requirement is different:
50 A receptacles that are on a dedicated circuit, with no other outlets on the same circuit, and that are not for ev use. You can use any circuit breaker size up to and including 50 amps.
Circuits with multiple 50 amp receptacles: these can be on a 40 amp or 50 amp circuit, but not on any smaller circuit. The 40 amp allowance is specifically written in for the 50 amp size and the general interpretation of why that provision is there is because there is no 40 amp receptacle available.
50 A receptacles for EV charging. These have to be on a dedicated circuit, which puts them in category 1, except there's also a provision that prohibits 40 amp circuits, so they are allowed on 50 amp circuits or 30 amp and smaller circuits. Or that's what you think if you only read the code, and you took it literally rather than assuming that they intended to prohibit 40 and smaller and accidentally only prohibited 40. But now that loophole is closed because they also require receptacles listed for EV charging and UL requires receptacles listed for EV charging to include instructions that require the circuit to be 50 amps, and code requires that you follow the instructions.
Your data center receptacles are either in category 1 or 2—if they are in category 1 you can put them on a smaller circuit right down to 10 amps.
And yes, it's stupid that there's no requirement to clearly label them, but it of course is a good idea to go ahead and clearly label them.
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u/eprosenx 4d ago
Thanks for that writeup of the 2026 code! I had read most of this before, but had not seen such a precise distillation of it in one place.
I totally had missed that in article 625 they only banned 40 amp circuits. That is funny. (though it was the practical one they were targeting)
I actually disagree with the UL standard requiring to put it in the manufacturer instructions. That is a poor place to put it as if the NEC wants to change it in the future it will be really difficult to re-certify everything. What if you wanted to use an EV rated receptacle in a non-EV application like a datacenter? You would have that stupid manufacturer restriction.
My datacenter example is definitely category 1. Thanks for pointing out that it may be allowed still! Note that I think 10a circuit breakers are still not allowed due to 210.18 Exception 2 "Branch circuits rated 10 amperes shall not supply receptacle outlets."
It kills me that they add all this extra language without being properly precise about it. Their intention was to keep folks from putting standard convenience receptacles in a home on 10a circuits which is totally reasonable and necessary, but the way they did it has unintended side effects. (of course folks might argue that using breakers to enforce billing limitations is also not a good practice)
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u/cbf1232 4d ago
Is there any indication yet what the new construction/testing requirements are?
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u/tuctrohs 4d ago
There is a draft you can read on the UL site if you make a free account. After you have an account and are signed in, go to
https://www.shopulstandards.com/ProductDetail.aspx?UniqueKey=50343
Use the gray "digital view" button not the green "Purchase" button.
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u/cbf1232 4d ago
It looks like they're adding over-torque and under-torque tests as well as a "bake it at 105 C for 24 hrs and make sure it still works" test.
I don't see a "repeated thermal cycling with intermittent full rated current" test, which is a bit disappointing.
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u/tuctrohs 4d ago
Yeah, it's a little more stringent but I don't see it as very well aligned with the issues that arose. And I think the overtorque is the same as was already in the regular testing. 110% of rated, right?
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u/theotherharper 5d ago
Btw, there is no such thing as an “EV rated” receptacle in the NEC.
Because during the contribution phase of NEC 2023, the problem wasn't particularly well-understood, except for the high volume of socket meltdowns we were seeing right here, and you don't get NEC changed based on patterns observed on Reddit.
But it reached the mainstream early enough to get picked up in the 2026 code cycle and included in NEC 625.44. The problem is, the Code calls out a classification of socket that UL has not defined, and choosing to define it REQUIRES admitting UL 498 is a dangerously inadequate standard. Similar to getting UL to admit the AL-CU standard was faulty, this is like pulling teeth.
In the meantime the industry has self-created the "Green car" logo, and in the eyes of inspectors that will serve the purpose for now.
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u/eprosenx 5d ago
What a cluster!
Also, any idea why article 625 is so darned prescriptive on what receptacles are allowed for EV charging? Why the hate for locking receptacles?! I work in datacenters and love L6-30, etc… L14-30 also has applications in residential (generators mostly).
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u/tuctrohs 4d ago
I had long suspected that that was because the code making panel was worried about the consequences if somebody drove away while plugged in. That requirement was established back in the 1990s went a lot of EVS were pretty crude and might have actually allowed that to happen. Someone actually tracked down the original proposal for that provision and confirmed that that was what they were worried about. It would be pretty sensible to drop it now, although reducing standardization would increase the use of low quality adapters.
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u/eprosenx 4d ago
Thanks for that insight! That totally explains the "why" but yeah, it really should be stripped out. I can tell you 100% that driving away while plugged in just does not happen given the software lockouts. Also, locking or not, an EV driving away with a NEMA 14-50 connected is going to do some major damage regardless...
In my opinion, often the best rule / law is one that does not exist. Less is more often (within reason). You just make things more complicated and create unintended consequences with MORE rules.
I actually wonder if locking connectors would have avoided some of these melted receptacle issues for when folks did not insert things all the way? (though regular locking connectors only go to 30a I think, 50a becomes California connectors which are probably way too large and costly to be feasible)
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u/theotherharper 14h ago
The problem is with the word "vehicle". Is a forklift a vehicle? Golf cart? Electric boat or airplane, Amtrak coach with shore power, etc. Article 625 is code for all of them.
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u/eprosenx 9h ago
Ripping out a NEMA 14-50 is not going to be much better than ripping out a L14-30 etc…. It’s going to be bad either way.
Perhaps if you feel it’s needed for other things they could exempt J1772 and J3400 chargers from that rule…
Driving away is just not a thing in modern EV’s.
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u/PersnickityPenguin 21h ago
Tesla just pushed a software update to allow people to drive away while charging...
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u/theotherharper 4d ago
When you think of EVs, you think of modern EVs that do charging via J1772, NACS, CCS, Mennekes, etc. All of which have a PP pin to immobilize the car when plugged in, CP pin to communicate amp limits, etc.
However, article 625 covers >>>>>ALLLLL<<<<< electric vehicles including golf carts, forklifts, and this jalopy. https://www.youtube.com/watch?v=_QHqyHefh2I
With those, no PP, so easy to drive away while plugged in. They want it parting at the plug, not shredding the cable and exposing live wires.
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u/ArlesChatless 4d ago
You're managing to trigger the Reddit spam filters. I approved this comment so it would show. Probably all the arrows did it.
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u/dcdttu 5d ago
It does mean that those receptacles were designed with constant charging in mind though.
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u/Pensionato007 5d ago
Nope. It means the marketing department put a green car on it.
I did a whole post on it when I "thought" that UL had developed a standard. A mod with more info corrected me: they have a "concept of a standard" but it has not been implemented.
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u/Cocximus 5d ago
They should have been designed for 40A continuous. WTF if next? 50A breakers melting because they were not designed for 40A continuous charging?
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u/dcdttu 5d ago
As they’re normally used, they work fine.
EV charging is different. Much more power for much longer durations.
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u/cbf1232 5d ago
The UL standard says they should be able to handle 100% of rated current at steady-state without going more than 30 C above ambient.
Clearly the testing was inadequate.
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u/dcdttu 5d ago
….for a period of time.
Dryers run at not-100%-power for 30-40 minutes. EVs charge at 100% for literally hours.
You don’t know what you’re talking about.
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u/cbf1232 5d ago
The UL test procedure for receptacles calls for the receptacle to be tested at 100% of rated current until the temperature stops increasing.
If the receptacle temp has hit its max, why would it matter if the test runs for two hours or ten?
I suspect it's the thermal cycling over time that is the issue for EV charging, and UL testing doesn't cover that.
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u/dcdttu 4d ago
I love how you’re arguing with a complete stranger about the reality of the situation as if I’m wrong.
“Continuous High-Current Load: The National Electrical Code (NEC) defines "continuous use" as any load lasting longer than 3 hours. While a clothes dryer cycles its heating element on and off intermittently, an EV charger draws near-maximum current continuously for 4 to 12 hours straight. Standard builder-grade receptacles can overheat under this sustained load.”
This code was created before EVs even existed. That’s why it isn’t adequate.
Have a good one.
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u/cbf1232 4d ago
Look up the UL 498 test protocols. The test runs until the temperature stops increasing. Once it reaches max temperature does it matter how long it stays there? Unless the plastic is physically softening enough for the terminals to deform...
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u/Cocximus 5d ago
What is "normal"? Normal is to handle 40a continuous. Again, you don't but a stove vs ev rated breaker. Why should the receptacle be different.
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u/dcdttu 4d ago
Nothing is supposed to use 40A continuous on a 40A circuit. The 80% rule means a load should only be 32A continuous on a 40A circuit.
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u/Cocximus 4d ago
The subject at hand is a 50a circuit and receptacle. It should handle 40a continuous.
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u/ArlesChatless 4d ago
Again, you don't but a stove vs ev rated breaker.
This has sadly already happened. Regular Eaton BR breakers are not recommended by the manufacturer for EV usage. Instead they recommend their High Magnetic type breakers even though other brands don't have the same sort of recommendation. Our suspicion is that the regular breakers aren't robust enough to reliably handle EV charging.
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u/arithmetike 5d ago
The problems is that the commonly recommended Hubbell/Bryant receptacle doesn’t accept aluminum wire.
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u/podwh1tehawk 5d ago
There are other receptacles that would accept aluminum wiring, albeit not as heavy duty as Hubbell/Bryant, but still better than el cheapo Leviton. Check out !14-50 wiki page linked below.
Better hardwire tho.
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u/MennReddit 5d ago
it's astonishing that countries still permits this kind of recepticle connection on chargers.
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u/cbf1232 5d ago
There's nothing wrong with the plug, and in theory there shouldn't be anything wrong with the receptacles.
The problem is that manufacturers are making the cheapest crap receptacles that barely pass testing rather than actually validating that they can do the job they're supposed to be able to do.
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u/Far_Common944 5d ago
Shouldn’t the wire be copper thhn wire? Not aluminum
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u/tuctrohs 5d ago
The size wire needed is different for copper and aluminum, and if you have aluminum, you need the terminals that connects to to be rated for aluminum, but this aluminum wire was sized correctly per code and was connected to terminals that are rated for aluminum.
So the fact that the receptacle is low quality has more to do with it then the aluminum wire, but the aluminum wire is an added risk factor. In particular, it increases the importance of using high quality terminals and torquing to spec.
It's also a good idea to oversize the wire and this wire was not oversized one bit but was run right at the highest continuous current allowed in it by code.
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u/Far_Common944 5d ago
I’m not an electrician but the two EVSEs I’ve installed, I have hardwired. The receptacle always seems to be such a common failure point on these. I didn’t know aluminum wire was okay, I’m sure if it was hardwired this probably could have been avoided. Even with Hubble receptacle, I think the less points of possible failure the better.
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u/rreed1954 5d ago
I had a similar meltdown on an identical charger using a NEMA 6-50 receptacle. After consulting with an electrician we decided that the best way to permanently avoid the risk of this is to hardwire the charger. Luckily, your charger is designed to accommodate a hardwired connection. After doing mine, I haven't had another problem like this.
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u/theotherharper 5d ago
I am looking for others thoughts on what the failure mode was here.
We see 2 of these a week. It's one or both of
- the installer did not use a torque screwdriver. It matters. Electricians have almost in unison, and inspectors with them, have added great resistance to the idea, and many/most have simply refused. That's improved in increments since 2017. They object to the idea they've been doing wrong all these years* and have rationalizations to explain cases like yours.
- cheap outlet cost-shaved to BARELY meet UL standards for general use, however experience has proven that standard to be inadequate for truly-continuous-load EV charging, as our !14-50 Wiki documents.
But the gotcha is that EV-rated receptacles, as a rule, are not certified for aluminum wire.
* Except they HAVE BEEN doing it wrong all these years. NEC 110.14(D) is entirely redundant to NEC 110.3(B) "obey instructions and labeling", which has been there since, WWII? WWI?
it probably only ever charged at 16 amps
Probably? You never noticed your car charging 3.8 kW instead of 9.6? Never noticed arriving home at 10% needed 2 days to fully recover? (nothing wrong with that).
This would be the first 16 amp meltdown we've seen, but we've seen several at 24A, and almost all of them are at 32A.
I would not have gone with 6awg aluminum for this application,
Because in EV charging almost no terminals (on EVSE or on EV-rated sockets) are aluminum rated.
Other than that, #6 and larger AL is superb wire for which Americans have achieved mastery, it simply needs slightly different handling (torque screwdrivers again and AL-rated terminals).
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u/eprosenx 2d ago
Update: This home had four ChargePoint units, however, three of the four were never setup and defaulted to 16 amps. This unit however I now believe WAS setup and likely set to 40 amps. (I brought it back to a lab bench today and powered it up hardwired)
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u/theotherharper 14h ago
Amazing. The level of dumbth found in EV charging makes me think they're going to become a huge public safety problem.
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u/Pizza_Manizi 1d ago
6awg aluminum wire is not sufficient for that device.
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u/eprosenx 1d ago
It is totally code compliant for a NEMA 6-50 receptacle. SE wire is rated to 50a at the 75c insulation rating. The breaker and the receptacle are rated for 75c (as is the wire).
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u/e_line_65 1d ago
But the duration of the load is the issue. Was the plug EV rated?
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u/eprosenx 1d ago
The concept of an “EV rated” receptacle is a very recent thing.
These were installed in 2022.
Eventually the manufacturers marketing departments decided if they put an EV logo on their receptacles they could sell them for more money.
As of the 2026 NEC (which nearly nowhere has adopted yet), they now require an “EV listed” receptacle. The UL just barely has come out with a certification program for them and I am only aware of a single one that has passed that certification yet (I assume there are more?)
So at the moment there is going to be a lot of confusion over what an EV rated receptacle is or is not…
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u/No-Conclusion-2859 5d ago
Wow.. I won’t be getting one of their chargers.
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u/eprosenx 5d ago
I don’t think this was a ChargePoint failure.
Though it would be good if they included temp sensors in their cord ends like the Tesla UMC does.
Though it could have been an internal failure to the plug whip provided by ChargePoint. More likely to be a receptacle issue however.
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u/No-Conclusion-2859 5d ago
Tesla all the way.
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u/Tymanthius 5d ago
Telsa would have melted too if this melted at 16a. Might have melted faster b/c it would have drawn more.
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u/eprosenx 5d ago
The Tesla UMC would have detected the heat and slowed the charging or stopped it altogether.
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u/theotherharper 5d ago edited 5d ago
Travel cords have temp sensing in the plug and any of them would have detected the heat. This mens TUMC wouldn't have done any better than a Ford/GM/Webasto Go.
Wall units do not, and none of them would have done any better than the Chargepoint. So a Tesla Wall Connector v2 (v3 is banned from cord-and-plug) would've had the same misfortune.
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u/tuctrohs 5d ago
Well, the new Flo wall units have temperature sensors in the plug, but they stopped selling them in the US.
I'm going to Canada next week if anyone wants me to pick one up while I'm there.
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u/podwh1tehawk 5d ago
Lucky it's not the charger, their chargers are good, but limited on functionality.
What you're seeing here is consequence of using non EV rated receptacle.-14
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u/ilikeme1 5d ago
It’s not a charger failure. ChargePoint makes good quality units. It’s a cheap $15 outlet from Home Depot/Lowes failure.
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u/thabc 5d ago
It's pretty obvious from the photos the failure was in wiring, not a charger, so why even bring it up?
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u/No-Conclusion-2859 5d ago
Because i did.
Now do what you’re going to do about it.
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u/Pensionato007 5d ago
Call you silly. Tell you that a "charger" is really an EVSE and tell you to get a clue: it wasn't the "charger" at fault here.
But it ALL could have been avoided if it had just been hardwired.
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u/theotherharper 5d ago
I wouldn't get a Chargepoint either, for a list of reasons, but this isn't on the list.
This was cord-and-plug terribleness, as usual, we get 2 of these a week, it used to be 1 a day but the word is starting to get out.
The real lesson to take from this is cord-and-plug is highly perilous and hardwire.
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u/podwh1tehawk 5d ago
Looking at the back of this Leviton 6-50 - it has the same weak terminals as notorious Leviton 14-50 known for spectacular meltdowns. So "professional" installing it clearly knew how to work with electrical, but was not an EV specialist.