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Use 50 Amp NEMA 14-50 Cord for 110 Volt /15 Amp?

So I've been carrying around a 50' 15A 110V cord (NEMA 5-15) for 110V charging with the Telsa Mobile Connector charger when overnight on the road and am going to buy a 30 foot NEMA 14-50 cord to give myself faster charging options when 220V 30-50A is available. I realize I'll need adapters for the various versions of NEMA 30A - 50A outlets. http://a.co/e9C0rOt

To minimize all the extra stuff I am schlepping around in the car (i.e. two extension cords), I started thinking in theory the NEMA 14-50 cord should be able to carry 110V/15A current when paired with the right adapter, which would allow me to stop carrying the 110V/50A extension cord, and just carry the 50A cord and a "NEMA 5-15 to NEMA 14-50 plug adapter." The NEMA 14-50 cord has 4 wires: Hot, Hot, Neutral, Ground. NEMA 5-15 only needs: Hot, Neutral, Ground, so this seems feasible to me.

I've Googled "NEMA 5-15 to NEMA 14-50" and haven't been able to find anything adapter like I describe commercially available. Is there an adapter available like this that anyone knows of?

If not it seems like something that could be wired up relatively easily with a trip to the hardware store, or am I missing something?

Thanks

SnowFlyer
 

BerTX

Active Member
Supporting Member
May 2, 2014
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Texas/Washington
So I've been carrying around a 50' 15A 110V cord (NEMA 5-15) for 110V charging with the Telsa Mobile Connector charger when overnight on the road and am going to buy a 30 foot NEMA 14-50 cord to give myself faster charging options when 220V 30-50A is available. I realize I'll need adapters for the various versions of NEMA 30A - 50A outlets. http://a.co/e9C0rOt

To minimize all the extra stuff I am schlepping around in the car (i.e. two extension cords), I started thinking in theory the NEMA 14-50 cord should be able to carry 110V/15A current when paired with the right adapter, which would allow me to stop carrying the 110V/50A extension cord, and just carry the 50A cord and a "NEMA 5-15 to NEMA 14-50 plug adapter." The NEMA 14-50 cord has 4 wires: Hot, Hot, Neutral, Ground. NEMA 5-15 only needs: Hot, Neutral, Ground, so this seems feasible to me.

I've Googled "NEMA 5-15 to NEMA 14-50" and haven't been able to find anything adapter like I describe commercially available. Is there an adapter available like this that anyone knows of?

If not it seems like something that could be wired up relatively easily with a trip to the hardware store, or am I missing something?

Thanks

SnowFlyer
Is this an RV 50a extension you are using, or a custom one for Tesla charging?
 
I think you would have to make adapters for both ends so you use the NEMA 5-15 adapter on the UMC and the car recognizes it is looking for 120volts, amps you can manually adjust down if necessary. If hand built this is may endup being more cumbersome than carrying the second extension cord. I completely get where you are coming from and if there were nice little molded adapters it could work great but once you start making things with a few inches of wire between I think they will get cumbersome quickly.
 
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This is the 30' NEMA 14-50 cord I'll be using:
http://a.co/e9C0rOt
71V6PKxlXOL._SL1500_.jpg

I just found this NEMA 5-15 to NEMA 14-50adapter, I think this is what I'm looking for. Does anyone see issues using this adapter and cord as described in my initial post?
http://a.co/7CeNNBI
61MwWBL1JSL._SL1500_.jpg
 
Last edited:

swegman

Active Member
Mar 27, 2012
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That 5-15 female plug to 14-50 female receptacle linked to above should work for plugging into a 120 volt 15 amp outlet, to which you plug the male end of the 14-50 cord into. But what adapter are you gonna plug into the female end of the 14-50 cable? You would need to find an adapter that has a male 14-50 plug and a female 5-15 receptacle (to which the 5-15 UMC adapter plugs into). I'm not sure whether such an adapter is commercially available, so you would likely have to fabricate the adapter yourself.

The adapters available for the UMC set the charging current for the UMC. That is, the 14-50 adapter sets the charger to draw 40 amps of currrnt, while, for example, a 14-30 adapter sets the charger to draw 24 amps of current. The charger itself does not care whether 120 volt or 240 volts is supplied to it, and the UMC adapters ignore the inputted voltage.

If you plug the 14-50 adapter from the UMC into the female end of the 14-50 cable, the charger will be expecting to draw 40 amps. At best the circuit breaker in the electrical panel will blow. At worst, a fire could start.

You can manually lower the charge rate in the car, but that's not recommended as it is known that the car will randomly revert to the 40 amp charge rate of the UMC 14-50 adapter (especially after a firmware update to the car).

At the end of the day, it is safer for you to simply carry 2 cables, a 14-50 (240 volt 50 amp) extension cable and a 120 volt 15 amp extension cable. That's what I do.
 
Here's the deal. So long as you can make the adapters, you're fine. The idea will work just dandy.

The RV "dogbone" adapter you have linked to is wired with neutral connected the neutral of the 14-50. You can use it if you make a matching adapter for the UMC end of the cord that's wired the same way so that you end up with a 5-15 adapter on the UMC. Making the adapter isn't especially cheap, and the two adapters will take up space, too. You might find it easier to just keep packing the 120v extension cord. But will work, and you can do it.

Some people try to use one adapter and plug the UMC with the 14-50 adapter directly into the extension cord with a single adapter on the other end. There are two problems with this. The first is that the wiring is different and the RV dogbone won't work. Second the UMC will think it's connected to a 50a circuit, and you'd have to dial the car down manually do avoid overloading the circuit. I don't recommend it.
 

BerTX

Active Member
Supporting Member
May 2, 2014
3,508
3,663
Texas/Washington
This is the 30' NEMA 14-50 cord I'll be using:
http://a.co/e9C0rOt
View attachment 284521

I just found this NEMA 5-15 to NEMA 14-50adapter, I think this is what I'm looking for. Does anyone see issues using this adapter and cord as described in my initial post?
http://a.co/7CeNNBI
View attachment 284520
Me, I'd get one of the charging extensions made for charging a Tesla, or make one myself. The Tesla does not need the Neutral wire, so these cables eliminate it making the cable 25ish% smaller diameter. This takes up less space, costs less (although the one I linked is only 20') is more flexible, and you could probably carry the 120v extension in the saved space.

Heavy-duty NEMA 14-50R extension cord for Tesla, 20 ft.
 
Okay, so I now understand the risk of using the wrong adapter (NEMA 14-50) on the UMC, which could cause the car to draw too much power, and potentially trip a breaker or worse, start a fire.

After looking at the 110V 15A extension cord I already carry, it weighs just 6 lbs and doesn't take up that much more room than the adapters necessary to allow the 50A extension cord to replace the 15A cord.

My 15A cord is 50' long, 20' longer than the 30' 50A cord. That extra 20' could be the difference between no juice at all and a 110/15A circuit.

Carrying the 15A and the 50A extension cords is the safer bet, it's cheaper (due to not having to buy or make more adapters, time is money), and offers more options than the one 50A cord and adapters scenario I was contemplating.

Thanks for all the info and advice,

SnowFlyer
 
If you tried without the 5-15 Tesla adapter I thought the car would recognize a low voltage issue. I know many of us have had issues with this with 120volt extension cord use.
Does the car recognize voltage ranges? Seems wrong if it only flags low voltage below 110volt somewhere. If getting 190 out of a 240 outlet I want to know before the fire.
 
If you tried without the 5-15 Tesla adapter I thought the car would recognize a low voltage issue. I know many of us have had issues with this with 120volt extension cord use.
Does the car recognize voltage ranges? Seems wrong if it only flags low voltage below 110volt somewhere. If getting 190 out of a 240 outlet I want to know before the fire.
190v is not an unusual voltage to get at a commercial site with a 208v nominal voltage.

The car doesn't recognize simple low voltage. It will happily work all the way down by below 100v. What it does recognize is a voltage sag where the voltage drops as the current ramps up (or just sags later) which is indicative of a potential overload. If you were to plug the car into into a 30a circuit with the 50a adapter, the car might see a sag and drop the current on its own, but it also might not and instead just keep pulling 40a until the breaker pops (if the wiring doesn't give out first). In the case of a 15a circuit, even if the car detected a sag, the car probably wouldn't back down far enough or fast enough to do any good.
 
If you don't mind paying extra, you could just extend your UMC to the length you want and carry 1 cord with the original Tesla adapters.

Tesla UMC extension

At $400 plus shipping it’s probably more than I want to spend on an extension... But very impressive capability. With up to 50’ of additional cord spliced on to the UMC in addition to the 20’ of cord already there, an owner could have a 70’ cord on the UMC able to charge from [email protected] up to [email protected] all in one device.

Do you have any idea how much 50’ of that cord weighs? Would it be comparable in size the the standard UMC cord or would it need to be heavier gauge due to the longer span?
 

Need

Active Member
Nov 22, 2017
3,262
2,608
Rancho Cucamonga
At $400 plus shipping it’s probably more than I want to spend on an extension... But very impressive capability. With up to 50’ of additional cord spliced on to the UMC in addition to the 20’ of cord already there, an owner could have a 70’ cord on the UMC able to charge from [email protected] up to [email protected] all in one device.

Do you have any idea how much 50’ of that cord weighs? Would it be comparable in size the the standard UMC cord or would it need to be heavier gauge due to the longer span?

No idea, but I am sure you could ask them. Someone posted that link on another thread so I thought I would share.
 
...

Do you have any idea how much 50’ of that cord weighs? Would it be comparable in size the the standard UMC cord or would it need to be heavier gauge due to the longer span?

You could do what the TMC spliced extension guys do and just buy the cable and DIY. Gotta have some supplies of course. There are a few shops on line that will sell cable directly. My J1772 box used the 40 amp cable from quickcharge here J1772 Cable

It's really flexible and weights one lb per 5 ft.
 
So I've been carrying around a 50' 15A 110V cord (NEMA 5-15) for 110V charging with the Telsa Mobile Connector charger when overnight on the road and am going to buy a 30 foot NEMA 14-50 cord to give myself faster charging options when 220V 30-50A is available. I realize I'll need adapters for the various versions of NEMA 30A - 50A outlets. http://a.co/e9C0rOt

To minimize all the extra stuff I am schlepping around in the car (i.e. two extension cords), I started thinking in theory the NEMA 14-50 cord should be able to carry 110V/15A current when paired with the right adapter, which would allow me to stop carrying the 110V/50A extension cord, and just carry the 50A cord and a "NEMA 5-15 to NEMA 14-50 plug adapter." The NEMA 14-50 cord has 4 wires: Hot, Hot, Neutral, Ground. NEMA 5-15 only needs: Hot, Neutral, Ground, so this seems feasible to me.

I've Googled "NEMA 5-15 to NEMA 14-50" and haven't been able to find anything adapter like I describe commercially available. Is there an adapter available like this that anyone knows of?

If not it seems like something that could be wired up relatively easily with a trip to the hardware store, or am I missing something?

Thanks

SnowFlyer
Not an expert Can you use a combination of Amazon.ca and https://www.amazon.ca/gp/product/B07ST5HN59/
 

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