mitch672
Active Member
Yes, they are horrible, heavy and they don't uncoil/straighten out very well.
See the thread I created on building my own: How to build a lightweight 50A extension cord
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Yes, they are horrible, heavy and they don't uncoil/straighten out very well.
See the thread I created on building my own: How to build a lightweight 50A extension cord
Yes it does look like a Nema 6-20, but set the charging amps to 16A, not 20A since you'll be drawing a continuous load for a long period of time. Let us know if it works! Apparently these are often used for motel AC units.
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Well, almost all household load panels are already unbalanced since there are a lot of 120V circuits in a house, all drawing random amounts of currents. At any one time, depending on how good the electrician was in guessing load patterns when he built the load panel, one phase is going to be drawing more current than the other anyways. The problem is that Tesla didn't realize there was a common 30A 120V supply (TT-30 in RV campgrounds), or didn't care.
This is incorrect. The neutral conductor from the transformer is sized to carry at least a 100A imbalance between the two legs for a new 200A service, and 20A is practically nothing in the scheme of things. Using the "entire winding" of your transformer (pole, pad, or otherwise) doesn't really come into play unless you were to have 100% of your loads at 120V on only one leg, exceeding the transformer's capacity.
If it was related to the maximum NEMA 5 receptacle size (there are NEMA 5-30's and TT-30's that deliver <125V at over 20A), then they would have limited the software to 16A to be compliant.
The 20A is likely some type of fail-safe, or Tesla just didn't consider the possibility of a <125V load over 20A and pulled a number out of thin air.
This is fantastic. I've already made 3 of them! Thank you Cosmacelf for sharing! I have a question for you and I hope you can help. I want to make an adapter to go from from a NEMA 10-50 to a 6-50 as well as 10-50 to 14-50. Since the 10-50 is an ungrounded receptable with a neutral and 2 hots, do I just wire the Tesla ground to the neutral on the 10-50? (Like you described on the 10-30 adapter?) Thanks a ton for any help you can give me. The PDF you created was really helpful!
John
John
And label them as such also. Putting "NO NEUTRAL CONDUCTOR" and "TESLA CHARGING ONLY" or similar, is really the best thing to do.
Hold on a minute: Cosmacelf (and FlasherZ, too!) - based on what you just told Johnster007, is it copacetic* for me to do the following?
* I have in my shop now a welder outlet: a 6-50.
* In lieu of my opening up the wall and conduit and such not in order to replace that with a 14-50 outlet, which would entail running a new wire - the ground - back to the main panel, can I instead make an appropriate pigtail, tying in the hot and neutral?
* It would seem to perform the same function, and safely so, knowing what occurs in the main panel with the ground and neutral buss bars.
*subject to the usual NEC and insurance, etc., disclaimers
* I have in my shop now a welder outlet: a 6-50.
* In lieu of my opening up the wall and conduit and such not in order to replace that with a 14-50 outlet, which would entail running a new wire - the ground - back to the main panel, can I instead make an appropriate pigtail, tying in the hot and neutral?
* It would seem to perform the same function, and safely so, knowing what occurs in the main panel with the ground and neutral buss bars.
*subject to the usual NEC and insurance, etc., disclaimers
It would be much cleaner and easier, and maybe cheaper (if you can get around shipping) to just buy this:
Shop Tesla Gear NEMA 6-50
EDIT: Wow! With nothing to judge scale that really looks like a NEMA 5-15 plug, which it is not.
Puyallup Bill
Member
Whoops! - beat me to it.
Note that Tesla markets a $45 6-50 adapter. All nice and legal. Of course by the time they add tax and shipping, it is going to be pricey.
http://shop.teslamotors.com/collections/model-s/products/nema-6-50
I know! Without having scrolled down your post enough to see your "Edit", I was thinking "What a dingle-dong. That's just a 15A plug!".
Question is, what on earth does the other end of that look like? A female 14-50?????? And if not.......
I know! Without having scrolled down your post enough to see your "Edit", I was thinking "What a dingle-dong. That's just a 15A plug!".
Question is, what on earth does the other end of that look like? A female 14-50?????? And if not.......
It plugs directly into the end of the UMC. It looks like a European two prong (cylindrical) socket, but with a ground. It also has a very small single pin to identify the adapter, and a latch mechanism/tab.
Like this picture I posted a few weeks back. Please note this is a damaged unit. You should not see the melting/discoloration.
If you have a 6-50 receptacle, just get a Tesla 6-50 adapter (replaces the 14-50 adapter that most people use on their UMC). If you live close to a Tesla service station, they usually have them in stock and it'll save you the ridiculous Tesla shipping fees. I'd double check that the breaker for the 6-50 is in fact a 50 amp breaker.
The 6-50, by the way, gives the UMC exactly what it needs - two hots and a ground. It does not provide a neutral, so no funky wiring is needed.
Here is a link to the FAQ, which covers the question:
FAQ: Home Tesla charging infrastructure QA
(Is it time yet to make it a sticky here, too? Seems I keep having to point there from here.
)First, placing a 14-50 would require you run a NEUTRAL (a/k/a NEC "grounded conductor"), not a GROUND (a/k/a NEC "equipment grounding conductor"). It is bad to use a ground as a neutral conductor (e.g., plugging an RV into a your 14-50 which needs 120V), because grounds are typically undersized relative to the circuit.
You're correct about them going to the same place under certain assumptions -- that you're working using a circuit that is connected to your service panel, where neutral is bonded to ground. However, in detached buildings or subpanels, the neutrals and grounds are handled differently. For example, the equipment grounding conductor in a detached building must be connected to grounding rods at the building, plus connected to the ground going back to the service panel, while the neutral runs back to the service panel.
Should you ever convert your 6-50 to a 14-50 and use the ground as a neutral, if there is a failure of the ground wire back to the service panel, the earth will be used as a current return path for 120V loads, rather than the circuit simply not working (resulting in strange effects).
If there's a Tesla adapter available, it needs to be the first option. Relatively speaking, $45 for the adapter vs. the safety risks and cost of building your own is an easy trade-off in my book. When Tesla doesn't offer an adapter, it's not always a good idea to rig something up unless you're in an emergency situation.
First, a dingledong correction to my "bullet" thread: of course I meant to write "tying in the GROUND and neutral". Duh.
Second, just to make Flasher happy - yes, this is to/from the service panel, which blissfully is only about 6 feet away on the exterior side of the same wall.
Third, I've read that FAQ several times...and forgotten the salient points at least as many..... ugh.
Fourth, after spending a good amount of this morning looking at website prices for various ends, etc., I have changed my mind about $45 seeming to be a high price for this little adapter. It now does indeed seem cheap!
Fifth, this is from the perspective of someone who has a small warehouse-worth of electrical, plumbing, construction, heavy equipment, whatthef****isthat stuff, accumulated over the past four or so decades - ever since the construction of the Trans-Alaska Pipeline, which is just over.....there....(about 700 yards), or even before, so, combined with the fact that a trip to town is either a 400-mile (Fairbanks), or 600-mile (Anchorage) round trip, I am firmly in the make-it-yourself-or-do-without camp and mindset. But, to the astonishment of my wife, I am changing.
Second, just to make Flasher happy - yes, this is to/from the service panel, which blissfully is only about 6 feet away on the exterior side of the same wall.
Third, I've read that FAQ several times...and forgotten the salient points at least as many..... ugh.
Fourth, after spending a good amount of this morning looking at website prices for various ends, etc., I have changed my mind about $45 seeming to be a high price for this little adapter. It now does indeed seem cheap!
Fifth, this is from the perspective of someone who has a small warehouse-worth of electrical, plumbing, construction, heavy equipment, whatthef****isthat stuff, accumulated over the past four or so decades - ever since the construction of the Trans-Alaska Pipeline, which is just over.....there....(about 700 yards), or even before, so, combined with the fact that a trip to town is either a 400-mile (Fairbanks), or 600-mile (Anchorage) round trip, I am firmly in the make-it-yourself-or-do-without camp and mindset. But, to the astonishment of my wife, I am changing.
Fifth, this is from the perspective of someone who has a small warehouse-worth of electrical, plumbing, construction, heavy equipment, whatthef****isthat stuff, accumulated over the past four or so decades - ever since the construction of the Trans-Alaska Pipeline, which is just over.....there....(about 700 yards), or even before, so, combined with the fact that a trip to town is either a 400-mile (Fairbanks), or 600-mile (Anchorage) round trip, I am firmly in the make-it-yourself-or-do-without camp and mindset. But, to the astonishment of my wife, I am changing.
I used to be that way. If I couldn't fix it myself, I didn't need it.
When it comes to electrical work, though, I've seen enough damage and loss and death to convince me that things need to be done right, and that was dealing with things like 10-15 amp loads. We're talking about continuous loads of 40 to 80 amps here, which are pretty serious when compared to most daily activities. When you see a 3/8x4" bolt turned into a 1/2" molten piece of slag, you have to respect the power of electrical current.
If you're qualified and understand the code and implications of what you're doing, by all means carry on... but if you don't know what you don't know, or you don't understand why it's a bad idea to cut the ends off a 100 ft extension cord and wire up a 50 amp plug and receptacle onto it, you might want to consider an electrician.
ClearwaterBchSteve
P445 / VIN 1794
@Cosmacelf: Your document is very well done and thorough - Nice Job! I built two adaptors on my own successfully using some of the same techniques. My dryer plug at home is really old. It's a NEMA 10-50 which is 3 straight blades at 60 degree angles. This provides a common and the two hots, but NO ground. Since the 10-50 does not provide ground, the UMC will not adapt to it as-is. My solution was to expose the ground lead coming from the female 14-50 connector the UMC plugs into. This I put into a regular extension cord ground and plug the cord into a grounded 110v outlet. It WORKS! Green light on the UMC and away we go. I run the current draw at 35A as the whole setup and fuses get rather warm (not hot). I've been using this setup regularly since December with no issues. This is a temporary solution until I get a permanent 14-50 installed specifically for the Model S but I have to replace my fuse box with a modern panel and it's a fairly costly upgrade.
On a recent road trip visiting family, I ran into a 14-30 dryer plug so I made a similar adaptor with $20 worth of parts from Lowes - (14-30 pigtail and 14-50 female receptacle).
On a recent road trip visiting family, I ran into a 14-30 dryer plug so I made a similar adaptor with $20 worth of parts from Lowes - (14-30 pigtail and 14-50 female receptacle).
40A continuous load / 50A rating requires a equipment grounding conductor of #10 minimum to ensure enough fault current flows to trip the breaker. Using an extension cord which will typically be 16 or 14 AWG, is not sufficient. While it will work because the UMC will pass ground validation, it is dangerous if there is a ground fault through the chassis of the car because it may not trip the breaker.
Thank you!
I agree with FlasherZ. The point of a ground is that if there is a fault inside the car/electronics (eg. a capacitor dies), the 50A current will be routed to ground and hopefully tripping the breaker. The problem with using a 120V socket ground as the ground is that it can't handle 50A, and the 120V ground wire will heat up a lot and may cause a fire before the 50A breaker can trip. So yes, it works now, but if a problem occurs, you don't have a proper failsafe and the problem could cause a fire (and actually the likelihood is pretty high if the ground comes into play). OR, I just realized the other likely possibility if a problem were to occur - the 50A current to ground will fry the puny extension cord ground, leaving no circuit path to ground, and thus leave metallic parts of the car charged at 240V inviting electrocution.
If I were in your situation, I would connect the 10-50 neutral to the UMC ground. At least then you have a ground wire that is rated for your amperage.
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The UMC does not make use of Neutral in it's 240V configuration. You can safely saw off or pull out the bottom blade, and then it will fit into 2 additional outlets: the 14-30, and the 14-60. Since the UMC will still attempt to pull 40A regardless, you will need to dial down your amperage in the car if connected to a 30A outlet. The safe value would be 24A to comply with NEC 125%.
If you do this mod, Then there is no danger from making X to 14-50 adapters that don't have the neutral, simply put epoxy in the bottom socket of your adapter to prevent someone from ever plugging in a "normal" 14-50. (assuming there will indeed be a neutral when it's not connected)
It's totally fine to connect the "Neutral" of a 10-50, 10-30, etc. to the ground of the 14-50 adapter if you do it in this manner. In fact, the molded Tesla adapters do just that.
It's also possible to put a switch on the UMC to force it to 24A when connecting to 30A outlets, but it's not easy, as the UMC is sealed. The elegant way would be to cut into the adapter and install a switch there. The adapter simply contains a ~9K resistor to ground to set the UMC to output a 40A pilot. If you replace this with around 33k, you'll get 24A (for 30A outlets), and then 72K will get you 16A (for 20A circuits).
-Phil
If you do this mod, Then there is no danger from making X to 14-50 adapters that don't have the neutral, simply put epoxy in the bottom socket of your adapter to prevent someone from ever plugging in a "normal" 14-50. (assuming there will indeed be a neutral when it's not connected)
It's totally fine to connect the "Neutral" of a 10-50, 10-30, etc. to the ground of the 14-50 adapter if you do it in this manner. In fact, the molded Tesla adapters do just that.
It's also possible to put a switch on the UMC to force it to 24A when connecting to 30A outlets, but it's not easy, as the UMC is sealed. The elegant way would be to cut into the adapter and install a switch there. The adapter simply contains a ~9K resistor to ground to set the UMC to output a 40A pilot. If you replace this with around 33k, you'll get 24A (for 30A outlets), and then 72K will get you 16A (for 20A circuits).
-Phil
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