Bag of Spare Adapters?

TM now has several adapters for sale. Is there much benefit to buying some or all of them to have on hand when out on the road?

Thanks jat. Yes, I have noted that several people have based their adapter collection around a 6-50 welder extension cord, probably for the reason you cite. The pigtail dortor referenced is 6-50R to 14-50P. You could then plug that into any of the 14-50 adapters sold by

@dortor - you made a slight mistake, the UMC seems to limit 120V charging to 20A, not 16A. The Tesla 5-20 adapter is limited to 16A, but if you were to make your own adapter to plug into the Tesla NEMA 14-50 adapter and plug into a 120V 30A power source, you would find that you could then draw a maximum of 20A (unfortunately not the 24A that would be the safe maximum).

Also, I want to update my Home Made Adapters document to reflect the new 5-20 adapter, but have been on the road since the adapter came out! Hopefully I can get to it this weekend.

In other threads I asked if 16 was the max-so ths is good to know...

So I think I'm going to go with gimp_dad's approach and base the set around a NEMA 6-50 extension cord. How does this one look?:

I would then get the 6-50 adapter from Tesla, the Hobart 14-50 to 6-50 adapter mentioned by dortor, a collection of 14-50 adapters from, and the TT-30 to 5-15 adapter mentioned by gimp-dad. That way I could use a single 50' extension cord and be able to plug into a variety of 50 and 30 amp outlets for RVs, driers, and welders, as well as 120V household outlets. I could also get the cordtec adapter mentioned by shop if I wanted to be more complete.

Anybody see a flaw in this plan? Remember, I'm looking only for parts I can buy, not build. Thanks.

@DouglasR - that looks fine, though with #8 wire you don't have any margin for using it in high ambient temperatures. Since it is black, just sitting in sunlight will help get it rather warm. Most welders have a pretty low duty cycle, while the car is going to be running continuously for hours. I personally would look for a #6 extension cord, but it may be hard to find -- if you stick with #8 just make sure it doesn't get to hot and be ready to dial the current down a bit if it does.

Other than that, sounds fine.

Thanks, jat. Maybe I should look for a 25' cord, but 50' is so much more versatile. And a 50' #6 cord would weigh a ton. My primary concern in getting these adapters is to charge in out of the way places or at the homes of people I visit, not necessarily to get the fastest charge. I therefore wouldn't mind dialing back the amperage a bit.

Hi DouglasR,

Here is the cord I bought:

Has worked great. The one you reference looks to be similar.

Note that you can also get a TT-30 to 5-20 adapter to add in case you get access to a 20A outlet:

I should update soon with a few other adapters that I now have (like the 6-20 and L6-20).

I made my own 6-50R to TT-30P pigtail adapter to Shop's specs to get from the 240V domain to the 120V domain. This is the key to using my welder's cable as a 120V extension cord as well since there are adapters for most of the standard 120V outlets and TT-30R.

I also bought the EVSEAdapters version but the first one was wired wrong so I made


Regarding the extension cord, I do prefer the blue color. The product description for the black Millspec cable does expressly state that it is rated for 50 amps, however, whereas the blue Anchor cord does not say that. Do you think there is a difference? The only other difference I see is that the black one has a handle.

Regarding the 240V-to-120V adapter, I don't see a 6-50R to TT-30P on the EVSEAdapters site. Were you referring to the 14-50R to TT-30P, which they do have? Do you think they have fixed their wiring mistake?

The anchor cord does say 50A on the tag on the cord and it is the same wire gauge as the one you reference. it does not have a handle.

Yes. The EVSEAdapters adapter I bought was the 14-50R to TT-30P. It is nice that it is not a pigtail. The one I got was, as I understand it, an early error in the wiring that has been resolved. They were very quick to fix the problem providing me a prepaid shipping label and turning the fix around very rapidly. I think you are fine using them.

And you are going to want the 6-50R to 14-50P anyway for those cases where you are at an RV park and need your extension cord. There is a high quality Hobart pigtail adapter for this:

Just noticed that my previous post (the one before the last one) got cut off.

I was just saying that while waiting for the EVSEAdapters 14-50R to TT-30P adapter I made a 6-50R to TT-30P pigtail by starting with a pigtail that had a molded TT-30P on one end and installing a 6-50R (wired correctly) on the other end. Thus I no longer really need the EVSE version but it is always good to have extra alternatives...

I bought the Milspec Direct cord directly from the manufacturer. They are in southern California, and I was able to talk to their engineer about how I intend to use it. It may not make much difference, but I like the fact that I could talk to the company. The price from Milspec was about $5 higher than from Amazon, but shipping was free, so it was about $20 cheaper in total. Also, they will print a message on the cord for free -- e.g., "Property of DouglasR (206)xxx-xxxx."

That custom imprinting is a very cool feature! Now I am jealous. :-)

Yeah, but it takes about an extra five days, which means I won't get it for the trip I was planning. Still, I thought of it as a theft deterrent.

So I finally got around to updating my Home Made Adapters document to include info about the new Tesla 5-20 adapter. Document available here:

Incidentally, I believe you can use the Tesla 5-15 and 5-20 adapters to make nifty little home made adapters for the 6-15 and 6-20 receptacles. The nifty part comes from the fact by using the Tesla supplied adapters, you won't have to remember to dial down the current since the adapters will limit the current to 12A or 16A respectively. And I'm 99% sure that those adapters are transparent to whatever voltage goes through them, so pushing 240V through the Tesla 5-15 and 5-20 adapters won't be an issue, and the UMC will then see 240V. As usual, use at your own risk!

@shop - have you tried it? I know when charging at 120V, the UMC cares which input line is tied to ground (via the neutral bus in the panel), and I thought it might be related to the adapter being used and not just keyed off the voltage. I personally haven't made any adapters for 120V at all.

I have not tried it. But I believe (but haven't broken open a Tesla adapter to verify) that all a Tesla adapter provides is a straight through connection from the 5-15 blades (hot and neutral) to the corresponding two hots on the UMC connector. So giving it 240V on the hot and neutral will just present 240V on the UMC two hots and the UMC won't know that it is connected to a 5-15. I think the only "signaling" in the Tesla 5-15 or other UMC adapter is a resistor between the two UMC low voltage signal pins which tells the car the amperage limit.

I finally have my bundle of PURCHASED adapters:

NEMA 6-50 adapter from Tesla
50' NEMA 6-50 extension cord from Milspec Direct
Hobart NEMA 14-50P to 6-50R adapter from Amazon
NEMA 14-30P to 14-50R adapter from
NEMA 10-30/50P to 14-50R "universal" adapter from
NEMA TT-30P to 14-50R adapter from
Camco NEMA 5-15P to TT-30R adapter from Amazon

The idea is to use a single 6-50 extension cord (three wire, so lighter), adapted to have a 14-50 plug, and then connected to any of several adapters designed to fit any outlet I am likely to encounter. Thanks to shop, jat, gimp_dad, and others who helped me figure this out (all errors are strictly mine, however).

I do have a question about the "universal" adapter from It is intended to be plugged into either a NEMA 10-30 or 10-50 outlet. However, it has a sticker that warns against setting the amperage higher than 24. Do you think that limitation applies to a NEMA 10-50 outlet as well as a 10-30 outlet, or would the adapter be able to handle 40 amps from a 10-50? I wrote to the maker of this adapter, but I haven't heard back yet.

Is there an extension cord made for the 220 cord we got from the factory. I may visit homes where the dryer plug in may not reach.

@DouglasR - that adapter is made with 8 gauge cable, so it is supposed to work fine with a 50 amp source, or a 10-50 plug, charging at 40 amps.

Thanks @shop.

@Rheumboy, use and input "extension cords." You will find plenty of information. Or read this thread.

The short answer is that while TM recommends not using an extension cord, many have done so with good results. You will need to decide what type of cord: RV cord, welder cord, dryer cord, etc., since it must fit both the outlet and the adapter you choose for your UMC.

Thanks DR!

For reaching distant 120V outlets, I have a NEMA 5-15 plug, which will connect to the car via several adapters and a NEMA 6-50 welder extension cord (described about five posts above). Can this setup be used with a 20 amp outlet as well as a 15 amp outlet? I am making two assumptions:

1. The NEMA 5-15 plug will fit into a NEMA 5-20 receptacle, and

2. Since the car thinks it is connected via a 6-50 plug, I should be able to set the car to charge at 16 amps rather than just 12.

Are my assumptions correct? I have yet to use this setup in the real world. Thanks.

Yes, it should work.

@DouglasR - you should not draw 16A from a 5-15 plug - the plug is only rated for 15A, and for a continuous load you have to derate that to 12A. You should use a 5-20 plug if you want to plug into a 5-20 receptacle and get 16A out of it.

Hmm. I have shop and jat disagreeing here. Does it make a difference that the 5-15 plug is actually an adapter with a TT-30 receptacle? This is the one:

What about trying it at 16A and seeing if it gets hot?

That adapter is rated for 1875W @ 125V, or 15A. The 5-15 plug is only rated for 15A, and that is not for continuous loads.

Generally, they have a lot of extra margin, but you are taking a risk. I've seen a lot of really questionable things done with electricity that didn't end in tears (the extension cord floating in the pool on flip-flops comes to mind), but there are plenty that do go badly. Personally, I stick with what is officially supported.

But if you have a 5-20 plug, why don't you simply use the Tesla 5-20 adapter and plug it in directly, rather than go through some adapter to TT-30 and then to a 5-15 plug plugged into a 5-20 receptacle? If it is just so you can use an extension cord, I would just use 6-50 as the base adapter with a 6-50 extension cord, and then make several adapters to the direct things you want to run (such as 5-20) rather than daisy-chaining adapters.

@jat - I don't feel confident to make these adapters myself. I have purchased the 6-50 adapter and extension cord, but the only way I can get that adapted to a 120V plug is to adapt the 6-50 to TT-30, and then TT-30 to 5-15. If I could find a TT-30 to 5-20, I'd buy that.

While home made adapters are good for special plugs and situations, in general it is always better to use the Tesla adapters IF they have one for your plug and IF you are within 20 feet.

Which may not be the case, hence my adapter document.

But be aware that you are taking a risk when you start putting together special adapters, extension cords, etc. Tripping over an extension cord is more likely to happen if the cord is long. And if you partially pull out a regular 120V extension cord, you might have a warm cable or plug. But if you partially pull out 240V at 30A, you might end up in more serious trouble.

Personally, if I were using a bunch of adapters strung together with an extension cord at a friend's house, I would be checking up on the connections every hour or so while people were awake. If they had kids running around, I'd probably use a lot of duct tape to keep things more secure.

As far as drawing 16A from a NEMA 5-15 plug plugged into a NEMA 5-20 receptacle, jat is being overly cautious. I can guarantee you that most 5-15 plugs are built very similarly if not identically (except for the sideways blade) to a 5-20 plug. Just use a beefy plug, and not something like a lamp plug.

Does it meet specs? No. Will it work without problems? Almost certainly. Note that even a perfectly within spec setup isn't 100% guaranteed to work either.

You can do your own test in your own garage. Find a 20A circuit, and use your proposed setup. Charge at 16A. Monitor the adapter at regular intervals, feeling it for excessive heat. Unplug it periodically, and feel the plug blades and see if they are too hot. If after several hours everything is OK, then that's a pretty good test.

@DouglasR - What are you using for the 6-50 to TT-30 adapter? The Tesla UMC is picky about which "hot" line on the UMC is hooked up to neutral on a 120V adapter. Unless it is designed specifically for the Model S, I think you have at best 50/50 chance of it working.

You could probably get the guys to make the custom adapters you need, since they already make custom adapters for the Model S and say they can do custom work.

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