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Question for you all. Kinda at my wits end with this one, it just doesn't make any sense to me.

I have had the issue of my Tesla charger dropping down to 16 amps from 32 amps after 30 minutes due to high outlet temperature. Turns out the usual culprit is the crappy Home Depot special Leviton 14-50 outlets that get installed. They're weak, aluminum and copper, and can't handle sustained 240V 32 amps for hours on end.

I decided to upgrade to the highly recommended industrial grade Bryant 14-50. It's obviously of tremendously higher quality, copper everything.

enter image description here enter image description here

The one thing is... I can't get my Tesla charger to work with it. I get an instant red light on the T of the Tesla mobile charger. When I plug my multimeter into the left and right terminals, I get 230V immediately.

enter image description here

I had to change the box to get the new 14-50 to fit, and thought perhaps I had a grounding issue.

To rule things out, I decided to just reinstall the crap Leviton.

Low and behold, boom. All green and all good on the Tesla charger.

What could be wrong here?

According to the Tesla Mobile Connector manual, no green lights and 2 flashing red lights = "Ground loss. The Mobile Connector detects a loss of ground."

Here's my wiring on the new Bryant unit: enter image description here

And here are the terminals on the old crappy Leviton: enter image description here

Update:

Made a proper ground this time. Same AWG wire all throughout. Found a trick on YouTube to make excellent connections, so I did just that... wrap the freshly stripped wires together at the end of the insulation with electrical tape to get them wrapped up with all the exposed copper leads tightly bound together, then take linesman's pliers and twist and the strands together gradually and slowly, until they've basically made a single large stranded wire. Then compress at the base, and clip the top edge to even the wire out. Then wire nut it together.

Got my in-lb torque wrench in today, and accurately torqued each lug down to 75 in-lb's as per spec by Bryant/Hubbell.

Still have the grounding error on the Bryant, and still have a happily working Leviton.

Hubbell unit comes in tomorrow, which will be a quick swap. With the count of people who had issues with the Bryant on my reddit thread now up to 5, I'm hopeful it's just a bad unit and the Hubbell will fire up once swapped out.

Please ignore all the extra wire and the hanging receptacle, at this point I'm just wiring it like it's on a test bench. I would obviously clean this up a lot before finalizing the installation. Just showing the new ground pigtail.

enter image description here

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    suspicion is you have 2 grounding wires together that might not make good contact
    – Traveler
    Commented Nov 28, 2022 at 5:44
  • What voltage do you get hot to grind and hot to neutral and neutral to ground? Commented Nov 28, 2022 at 6:07
  • Hot 1 (XXX - Black) 118.1V Hot 2 (YYY - Red) 119V Neutral - 0V
    – amgdart
    Commented Nov 28, 2022 at 6:32
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    Also: the Bryant is really picky about ground wire size. I ask for a picture because if you're trying to do two ground wires like the Leviton rather than a proper full-size pigtail, you'll probably have this error. Install it correctly using a pigtail if that is the case.
    – KMJ
    Commented Nov 28, 2022 at 6:41
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    Thanks for the reply. Yeah, I've got two wires in the ground. You can see the Bryant install in the second to last photo. I'm going to try to run the proper pig tail now.
    – amgdart
    Commented Nov 28, 2022 at 6:49

4 Answers 4

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Update here.

So I had 5 reports on my Reddit thread of others who ordered the same Bryant unit I did, had ground faults, and after reinstalling the Leviton immediately had no ground faults. Every single one replaced with the Hubbell 9450A, and didn't have an issue.

Well, I did the same. Yes, my grounding was set up wrong, I fixed that grounding. Still no dice with the Bryant, but still good I fixed my grounding.

New Hubbell came in today.

Uninstalled the Bryant, installed the Hubbell, torqued to 75 in-lbs, fired up the breakers, tested the lugs with the multimeter for voltage, plugged in the Mobile Charger, and boom. No ground faults, 32 amps of charging with 2 hours so far running way way cooler (tested with my thermocouple) vs. the Leviton, no issues with the Mobile Charger thermal throttling like the Leviton.

So there's a datapoint for anyone wanting to retrofit out the inferior consumer grade Leviton to an industrial 16-50. Get the Hubbell 9450A right off the bat, don't bother with the Bryant.

I'm sending the Bryant off to a user on Reddit who is an electrician to play with and test seeing as so many people have had issues in order to see if he can find a crucial issue in the unit that is causing so many failed installs.

Anyway, problem resolved. Thanks to everyone for your input, and hopefully I added a nice datapoint and can be of help to someone out there who is intending on taking on this project themselves.

(To be clear, obviously you should never leave this install as in the photo. I've been running it like this with the breakers within arms reach during troubleshooting mode. The ground will be shortened, cleaned up, and everything backed into the box and a faceplate installed.)

enter image description here enter image description here

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  • It's hard to tell from the photo, but it still looks to me like there are 3 ground wires under the screw on the receptacle, not a proper pig-tail. Hope that doesn't get inspected...
    – FreeMan
    Commented Oct 19, 2023 at 14:19
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Harper's Rule: when something doesn't work, and something else is improper/not right/not to Code, no matter how totally unrelated it seems... fix it anyway - it often cures your problem.

In this case, the ground wire to the receptacle is improper. Correct the issue with the ground wire.

Note that the supply wire must go to a metal box first. In many cases, ground will automagically be delivered to the socket via hard metal-metal contact with between steel box and metal receptacle yoke.

I suspect you are doing your testing with the receptacle not physically mounted, and so that passive grounding is not happening. It's falling over to the hokey ground and that's not working.

Also, the way connections are made more secure is NOT by making them out of copper. Copper is actually a poor lug material. Connections are made secure by torquing them to specification per NEC 110.14. Failing to do so will cause poor connections and overheating as you saw on the earlier outlet.

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  • Thank you for your input. I actually have all these in the works today. Ground directly to the box, then pigtailed properly over to the receptacle. Also grabbed a torque wrench to get those terminal screws up to the spec requested at 75 in-lb's. The receptacle is actually already physically mounted.
    – amgdart
    Commented Nov 28, 2022 at 21:28
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Frame Challenge: Switch to Hardwired Connection

(But with an oops, see below. But despite the oops, I am posting this answer as OP may actually agree and in any case future people reading the question may be helped by this answer.)

People use a plug/cord/receptacle because they're used to it.

But think about it: Once it is working properly, how often will you unplug the Tesla EVSE (a.k.a., charger)? You probably won't even take it on vacation - you either use the emergency plug-in 15A 120V cord (slow charging, but works if you have nothing else; which you should keep in your car as an emergency backup) or you stop at a Supercharger. Do you have anything else (e.g., welder) that you plug into the 14-50 receptacle occasionally? The vast, vast majority of people do not.

Now look at it a different way: Do you unplug your furnace/air conditioner (excluding window units, of course)? No. You can't - it is hardwired. If you have an electric water heater (tanked or tankless), do you unplug it? No. You can't - it is hardwired. (I would use the same argument for oven, disposal and dishwasher but some people actually have those plugged in to receptacles (mine are all hardwired) - but even then they never unplug them except for repairs.)

Unless you need to move the EVSE frequently or use the 14-50 receptacle for something else, there is no good reason not to hardwire the EVSE instead. There are, generally, three things to consider:

  • Disconnect. As I understand it (the code experts can correct me if I'm wrong), you need a disconnect of some sort visible and within a certain distance of the EVSE so you can shut it off in an emergency. If it is connected to a breaker in a panel in the garage then you're all set. If not, you may need to add an actual disconnect, which actually is not a big deal. Here is a GE 60A disconnect from Home Depot:

GE 60A Disconnect

and the great part - it costs all of about $15!

  • Wire Connections

When you connect together wires for a typical 15A, 20A or even 30A circuit, most people (in the US) use wire nuts. Cheap and easy. They are not necessarily available in the sizes you need for use with 50A circuits. But guess what? The disconnect will connect to big wires, so you've killed two birds with one stone.

  • Device Must Be Designed for Hardwired Connection

This is the oops. I assumed, incorrectly, that you were trying to use a Tesla wall connector. You are actually using (stated in the question) a mobile connector. The mobile connector is designed for plug/receptacle use. The wall connector is designed for hardwired use. In fact, the wall connector says Do NOT install cord-and-plug type connections. (It also says disconnect not recommended, but allows it and in fact it may be required by local code, but if you don't need a disconnect then you can connect the existing wires directly to the Tesla Wall Connector.)

Unfortunately, the Tesla Wall Connector currently costs $400. Which is actually a competitive price compared to 3rd-party EVSE equipment, but only you can decide whether it is worth getting this. It is arguably the right way to install for your primary (e.g., home) charging location.

Net cost, if you want to keep the Mobile Connector at home and plugged in all the time but still have a spare for emergency on-the-road or destination use, is actually less, as getting an additional Mobile Connector will cost you $230 - i.e., net cost for Wall Connector vs. a second Mobile Connector is close to $200.

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    There are useful frame-challenge answers, and then there's "six hundred words telling the OP to spend an extra $400 when they already have a usable charger"
    – nobody
    Commented Nov 29, 2022 at 3:09
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    @nobody Given the number of posts that seem to assume that "plug/receptacle is the best way to install EVSE" it made sense to me. Plus, I didn't actually notice at first that OP actually had a Mobile Connector (which is why I called that an "oops", it really was). But I stand by my post despite the (for now, at least) Net 0 votes. Commented Nov 29, 2022 at 3:13
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    Yeah absolutely, I think hardwiring is the way to go. This is just a retrofit of an existing installation to get a poor quality receptacle that will overheat when trying to charge at 32 amps swapped out to the Tesla recommended industrial unit. If I was doing a fresh install that I would be paying an electrician for I absolutely would get the hard wired charger and probably be able to get a rebate along with it, but as mentioned this is just a retrofit.
    – amgdart
    Commented Nov 29, 2022 at 4:09
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Occasionally Bryant/Hubbell 14-50 outlets have misshapen ground internal terminals. Non-ideal QC. This can lead to open ground faults. You can check the ground terminal by inserting a 17/64” rod/drill bit into the outlet’s GRD hole and feel for slight drag. A 9/32” rod will require a firm push to pop in and will have significant drag. Reminder to power off first.

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