nwdiver
Well-Known Member
Well.... I may have connected the GND and Neutral to get "3" wires. It may have definitely worked :wink:.
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It may work but it is DEFINITELY a violation of code, not safe and can cause all sorts of problems. You should not do that.
(There is a reason they keep ground and neutral separate, or we simply wouldn't have separate conductors.)
Please, buy a HPWC!
You can set it to any Amperage you want, so set it to 40A and charge with that.
A HPWC is a LOT safer then using a UMC every day. The Nema sockets are simply not designed to be unplugged every day. Over time it will cause wear and tear on the connector which will increases resistance thus more heat builds up.
Don't try to save money on the charging infrastructure. Buy a HPWC, install it and leave the UMC in your trunk/frunk for the occasional charge at a RV site or so.
The HPWC is really the best and safest route.
widodh,
I would not be unplugging the UMC very much. I would think maybe 5 times a year. I get mixed comments reading the many threads on the UMC. Do you really think the UMC is that unsafe.
I would not be unplugging the UMC very much. I would think maybe 5 times a year. I get mixed comments reading the many threads on the UMC. Do you really think the UMC is that unsafe.
With all the connectors and adapters in place I don't think the UMC is a safe option for every day use.
On the NEMA side it doesn't lock into the socket, so it could be unplugged while 40A is flowing over the contacts. The HPWC is a fix installation which locks into the car and cannot be unplugged while current is flowing.
A NEMA socket can be halfway inserted causing less surface to make contact which again leads to more heat.
In the UK Tesla isn't even supplying the UMC anymore, they recommend getting a fixed EVSE at home. You have to buy the UMC separately if you want want.
If you are spending >$80k on a car, please, don't try to save money on charging infrastructure.
roblab
Active Member
RV parks use NEMA 14-50s. They are certainly plugged and unplugged several times a month. Maybe several times a week. It is an outlet. It is designed to be used as an outlet. People have been using them for years as outlets.
Tesla measures resistance and is able to cut the current, or even stop using a leg if there are problems, on the UMC.
Building your own 6-50 adapter is simple, and safe if you know how to tighten a screw. Combining ground and neutral works fine with charging, and, as some of you know, ground and neutral are combined in the circuit breaker box anyway. What's the problem with combining it 20 feet further down the wire? I build my own, it works beautifully, and I trust it.
For those of you who are unsure, uncertain, afraid of electricity, don't understand it, etc., buy the expensive, unnecessary HPWC. If it lets you sleep easier, then it's worth it. Or buy an interconnected radio frequency smoke alarm, one sitting above your dangerous outlet, and the other in your bed room, which will cost about $65. Or hire an electrician, some of whom have been known to do sloppy dangerous work because they are in a hurry, or new, or sick, or.... I follow up any electrician and inspect the work on my home, and I know I often do a better job myself.
Of course, there are good electricians out there, but it's not rocket science. That's what Tesla and SpaceX do.
Strong statements to throw around (that it's not safe). If I only unplug my UMC twice a year, there's no additional wear. Are you an electrician? Does the construction violate any standards?
I'm not sure I'd go so far as to say that the UMC is "unsafe" for every day use. But I agree with you that in principle it is not the best option for every day use. It does have the multiple connection points, it is not as sturdy of a design. I suspect you'd be much more likely to need to replace it every few years whereas the HPWC will likely be a lifetime device.
There are also a few reports out there of folks who unexpectedly found themselves stranded for a charge w/o their UMC b/c of the habit of leaving their UMC plugged in at home.
So, either purchasing a second UMC to always leave in the car and to act as a backup in case of failure of the daily use one, or, as suggested, buying the more durable, nicer looking, longer corded HPWC...that's the option I like as well.
You have to think about "the mass" buying a EV.
Have you ever seen how most people use extension cords? They don't think about it, they simply plug it in and think it's OK. We are talking about 40A continues load for hours at a time. That can potentially cause issues.
The HPWC has been designed to take the "idiot" out of the equation. With the UMC you can still halfway plug in the NEMA connector which is dangerous.
So my statement about the UMC not being safe for every day use still stands. Potentially users can use it improperly and cause a dangerous situation. With the HPWC that's a lot harder to do.
Exactly. Anything else is FUD. I use only the UMC for charging, and plug/unplug it at least once a day. After 14 months, there are absolutely no problems, and no additional heat. Apart from the early UMC failures where they just stopped working, I have had no problems.
Some RV parks have outlets that are well over 30 years old, and probably tens of thousands of plug/unplug cycles, and they don't even get very warm when charging at 40A for 7 hours straight. That tells me that some people here are blowing the plug/unplug cycle problem way out of proportion.
There is a problem with the UMC adapter end though, and any gap in between the adapter/UMC(very easy to do unless you are paying close attention) will cause major heat, and possibly melting. That is where the problem lies, and unfortunately Tesla has only come up with band-aid fixes so far.
jcaspar
Member
I would just put a 14-50 plug in using the same wiring but just not wire the neutral. This is TOTALLY safe if you just use the UMC in it. Label it and just be sure to change it back to the 6-50 if you ever move. If you can run a neutral you can wire the 14-50 by code but this will not make using the UMC any safer.
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If your trying to imply the HPWC is best for idiots, you might be right but I think the UMC is perfectly safe for the rest of us...:wink:
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If your trying to imply the HPWC is best for idiots, you might be right but I think the UMC is perfectly safe for the rest of us...:wink:
Not to be an ass, but these statements are somewhat incongruous. :wink: If "you know enough to do a better job yourself", then you should know why you shouldn't merge ground and neutral more than once in the house. Multiple ground-neutral bonds results in the ground wire functioning as a current carrying conductor from the second bonding back to the service entrance, which risks non-zero voltage on the grounding system. This is "A Very Bad Thing" (TM). Google "multiple neutral ground bonds"
The NEC doesn't exist to make life difficult. It exists to (hopefully) prevent people from doing potentially dangerous things or things that might be mis-interpreted by people making modifications to the wiring in the future.
Now here's a statement I can agree with. I once lived in a condo where a supposed "pro" wired hot to ground on an (infrequently used) outlet. I plugged in a trouble light with a grounded frame and got bitten.
If presented with a 3-wire 6-50 outlet and no 6-50 adapter, I'd probably build one of Cosmacelf's adapters: http://cosmacelf.net/Home Made Adapters.pdf Another (but less legal) option would be to replace the 6-50 with a 14-50, leave the neutral unconnected, and label it to avoid future confusion.
@widodh - Point of clarification. With your safety concerns, are you referring to (a) the UMC itself, (b) the connection point between the UMC and the vehicle, (c) the connection point between the UMC and the adapter, (d) the connection point between the adapter and the NEMA receptacle, (e) the connection point between the NEMA receptacle and the wires leading to the switch box, or (f) some combination of the above?
Not easily. A 14-50 requires an extra wire (the neutral). You can hack it to work with Tesla charging with only three wires, but it won't be to electrical code, and I would never ever recommend leaving something in a house that is intentionally not to code. The next guy to buy the house might get a rude surprise....
The only proper way IMHO to use a 6-50 receptacle with a 14-50 Tesla adapter is to build a NEMA 6-50 to 14-50 adapter and label the adapter for Tesla charging only. This way you aren't messing with house wiring.
If you really want to convert the plug to a 14-50, then run a new wire for the neutral.
Actually, the BEST way to handle this is to get a HPWC. At least you are gaining something from this. The HPWC is more robust than the UMC. It would allow you to leave the UMC in the trunk.
If you really want to convert the plug to a 14-50, then run a new wire for the neutral.
Actually, the BEST way to handle this is to get a HPWC. At least you are gaining something from this. The HPWC is more robust than the UMC. It would allow you to leave the UMC in the trunk.
If you don't have the UMC with you you can use any of the 1000's or J1772 charging stations or superchargers out there.
The UMC would only prevent you from being stranded at a RV park or something like that, so you're probably on a road trip. Remembering to put the UMC in the car after you unplug when you leave for the trip is not that hard and, at least for me, not a good reason to spend another $600 for a 2nd UMC or $1200 (plus $440+ to install) for a HPWC.
You're right, it won't do anything for the UMC (since it doesn't use the neutral), but it is not "TOTALLY safe". You must assume that someone could use that standardized outlet in a standard way. Just less than a month ago, I used a 14-50 on a pedestal in a campground that had a broken neutral. I used it fine, but the neighboring RV came quickly to warn me that he had problems with it because his appliances all acted strangely.
I don't care if it's at your house or on a campground, if it's a 14-50 it's supposed to be 250V/125V, 2 hots, a neutral, and a ground.
Good news the Tesla SC scored me a 6-50 adapter so I am set.
A very interesting thread though - thanks for all the suggestions.
A very interesting thread though - thanks for all the suggestions.
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