Bag of Spare Adapters?

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?

shop | August 4, 2013

Here was the link I was looking for, a 10-30 extension cord. But as others have pointed out, you have to figure out if you need a 14-30 or 10-30.

cybrown | August 4, 2013

Couldn't I buy a 14-50 extension cord and remove the neutral pin on the plug end? Then it would fit 14-30s and 14-50s. I realize I'd have to label it "For Tesla Charging Only", but this would work, right?

DouglasR | August 7, 2013

Of the many adapters discussed in this thread, I haven't seen any mention of a NEMA 14-50R to NEMA 6-50P (unless I missed it). The purpose of such an adapter would be to use a 14-50 RV extension cord with the Model S to plug into a welder outlet. I also didn't see this adapter on Does anyone know whether such an adapter can be purchased anywhere? Am I missing something as to why it does not appear to be available? I have seen adapters going the opposite direction, i.e., 6-50R to 14-50P. Thanks.

dortor | August 7, 2013

the easiest thing to do is to build a NEMA 10-30/14-30P to 14-50R plug…cause then all you need is a 14-50 extension cord

using shop's excellent document you can find NEMA 10-30/14-30 "wire/pig-tails" - a plug on one end and bare wire on the other - you then buy the Camco RV 14-50 50AMP connector (female/14-50R) and wire it up…

My recommended "recipe" for any type of plug is:

a) find a "connector/plug" already made with the type of plug you need - even if the other end is the "wrong" type of plug/receptacle …
b) chop the "wrong" end off the wire - strip the wire leaving the "right" plug-receptical attached
c) using the stripped wire attach it to a Camco 55343 RV 50 AMP female connector - this is a NEMA 14-50R connector (R = receptacle/female connector)

d) Now you can use the stock Tesla 14-50 connector for the mobile charger
e) dial the charging AMP's in the car down to 80% of the rated breaker for the plug you are currently using
f) by converting everything to a NEMA 14-50R connector you can then purchase a NEMA 14-50 extension cord…

NOTE: there are two basic choices here - NEMA 14-50 or NEMA 6-50 - extension cords are easily obtainable for both types of plugs/receptacles…

your only choice here is length and type of plug

when building your "adapters/pigtails" build them to match your extension cord, and then you can use the Tesla 14-50/6-50 adapter for all types of plugs…

dortor | August 7, 2013
dortor | August 7, 2013

careful reading of the following documents will tell you all you need to know

dortor | August 7, 2013

changes to my charging kit that I carry with me:

I have ditched my 120v NEMA 5-15 extension cord in favor of a 20AMP NEMA 5-20 extension cord - with the proper pig-tail or adapter this one extension cord can be either a NEMA 5-15 cord or a NEMA 5-20 cord

I have also purchased a NEMA L5-30 adapter to deal with a plug I encountered at a motorsports venue last weekend

I ditched the home made NEMA 5-20 adapter shop's document made in favor of the new Tesla 5-20 adapter (thanks shop! sorry shop!)

NEMA 5-15 to NEMA 5-20 adapter pig tail

NEMA 5-20/5-15 Extension cord

when dealing with a "normal" 5-15 house hold plug this extension cord will work with the adapter listed above

NEMA L5-30P to NEMA 5-20R/5-15R - found in certain outdoor/wet locations
this is 120V/30AMP connections

Not sure the 30AMP's does you any good cause Tesla software doesn't allow AMP settings above 16 amps for 120V power sources

NEMA 5-20 adapter from Tesla

dortor | August 7, 2013

I forgot to post the link the NEMA L5-30 pig-tail/adapter - here it is…

DouglasR | August 7, 2013


I don't feel up to building the adapter; I'm looking to purchase one. However, I think you misread my post. I want a 14-50R to 6-50P adapter or pigtail. That is because I want to use a 14-50 extension cord and plug into a 6-50 welder outlet. Unless I'm missing something, none of the links or items you described will do that.

jat | August 7, 2013

@DouglasR - just like the 10-30 adapter, you aren't likely to find one, because you are either tying the neutral conductor to ground or leaving it unconnected -- either case is dangerous in different scenarios, and the only safe use of such an adapter is with something that leaves the neutral unconnected when plugged into the 14-50 end. You are more likely to find the other direction - get a 6-50 extension cord, and an adapter to plug the 6-50 plug into a 14-50 outlet (safe, since it just doesn't use the neutral connector), and then use the 6-50 adapter on the Tesla UMC.

Or, you can build your own / find someone willing to build a custom cable for you.

DouglasR | August 7, 2013

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

shop | August 8, 2013

@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.

dortor | August 8, 2013

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

DouglasR | August 8, 2013

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.

jat | August 8, 2013

@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.

DouglasR | August 8, 2013

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.

gimp_dad | August 8, 2013

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

DouglasR | August 8, 2013


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?

gimp_dad | August 8, 2013

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:

gimp_dad | August 8, 2013

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...

DouglasR | August 8, 2013

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."

gimp_dad | August 8, 2013

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

DouglasR | August 8, 2013

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.

shop | August 22, 2013

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!

jat | August 22, 2013

@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.

shop | August 22, 2013

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.

DouglasR | August 24, 2013

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.

Rheumboy | August 24, 2013

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.

shop | August 24, 2013

@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.

DouglasR | August 24, 2013

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.

Rheumboy | August 24, 2013

Thanks DR!

DouglasR | September 5, 2013

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.

shop | September 5, 2013

Yes, it should work.

jat | September 6, 2013

@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.

DouglasR | September 6, 2013

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?

jat | September 6, 2013

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.

DouglasR | September 6, 2013

@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.

shop | September 6, 2013

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.

shop | September 6, 2013

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.

jat | September 6, 2013

@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.

DouglasR | September 6, 2013

@jat - I am using the NEMA TT-30P RV Plug to 14-50R Adapter, made expressly for the Model S.

I believe the first version of this adapter did not work for the reasons you cite, but several people on this forum state that the revised adapter works fine.

Thanks jat and shop for your input. I will try testing this configuration before I need to use it.

jat | September 6, 2013

@DouglasR - that should work fine then

Brian H | September 7, 2013

Speaking of kids and cords and lamp plugs, one day many moons ago my 4-yr old decided to see if my pliers/wire cutter/stripper would remove the plug from a lamp cord by cutting the wire. While it was attached, and the lamp plugged in. The bang it made vaporizing about ¼-½"sq. of the cutting edges was quite dramatic. The handles were rubberized, so no fatalities occurred.

JPPTM | September 7, 2013

BrianH-I did the exact same thing as a kid with a pair of insulated diagonal cutters. Not only did it burn 2 clean holes along the cutting edge, but it also welded the hinge. I was duly impressed... :)

plusplusjames | February 1, 2014

This discussion seems to be way too complicated.

Two places I visit have NEMA 10-30 outlets. Why should I buy any of the adapters above and dial down the amps when 1) I can buy a NEMA 10-30 adapter from Tesla for $45 and then 2) an extension cord with 10-30 on each side?

Is that too simple of a solution?

d_kaufman | February 1, 2014

If all you need is a 10-30, it is a perfect solution. The complex collection is if you feel you may need any of a number of adapters, and extensions. The ideal is to carry only one extension because to be rated for high current they tend to be quite heavy and bulky. After you have chosen one extension you choose the appropriate adapters, and then may have to dial down current.

negarholger | February 1, 2014

@plusplusjames - it originated from the time before Tesla had many adapters... I used a 10-30 home made adapter for the first about 6 months until after much asking finally they had a couple at the factory and I got one.

plusplusjames | February 1, 2014

Thanks for the get-backs. My 10-30 solution looks pretty good except for the $150 extension cord.

logicalthinker | February 1, 2014

Ha - I had missed your post Brian H.

When I was a kid my brothers and I tried to make light bulbs. We stripped old copper wires and shaped a filament, and inserted the ends into an extension cord which we then plugged in. It did glow red momentarily... Then it went pow, right at the moment the circuit breaker flipped...

We had so much awesome fun in our attic.

I did successfully make a microphone.

DouglasR | February 1, 2014

@plusplusjames - If you only visit two places, then you don't need all of this. If you like to drive off the beaten path, where you may not find the type of outlet you need, or you may not be able to get close to the outlet you need, then the extension cord and "bag of adapters" can be a lifesaver. I can charge so long as I get within about 70' of a drier, welder, RV, or standard 110 (15 or 20 amp) outlet. That has come in handy several times.