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Tapping into Wall Mounted Connector to get 240 V, 25 amps or so.

PhysicsGuy

Member
Apr 16, 2020
98
89
California
I have a wall mounted connector that can go up to 40 amps. (See picture below). For weird reasons that I can explain (basically distance related) I would like to be able to tap into that safely to get ordinary 240 volts with some sort of appropriate NEMA plug that I can plug into with a good 240 volt extension cord. I would be happy getting 20 amps out of that (and only use it when the wall mounted connector is not in use). Does that sound like a reasonable endeavor? What would that tend to involve? Would love to hear from experts here.
Also, what NEMA would you suggest for the plug I have installed and the 25 to 40 ft extension cord I plan to buy and use? What would be compatible with the onboard charging stuff from Tesla? Thanks a lot.

PS. This would be a dry weather only option. I would not expect to be able to use the extension cord option in the rain.
 

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stopcrazypp

Well-Known Member
Dec 8, 2007
10,203
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I have a wall mounted connector that can go up to 40 amps. (See picture below). For weird reasons that I can explain (basically distance related) I would like to be able to tap into that safely to get ordinary 240 volts with some sort of appropriate NEMA plug that I can plug into with a good 240 volt extension cord. I would be happy getting 20 amps out of that (and only use it when the wall mounted connector is not in use). Does that sound like a reasonable endeavor? What would that tend to involve? Would love to hear from experts here.
Also, what NEMA would you suggest for the plug I have installed and the 25 to 40 ft extension cord I plan to buy and use? What would be compatible with the onboard charging stuff from Tesla? Thanks a lot.

PS. This would be a dry weather only option. I would not expect to be able to use the extension cord option in the rain.
Seems like it may be a code violation to just tap into that without having something to ensure you will never be able to use both loads at the same time.

You can do what people do when they have dryers they want to share a circuit with and just get a double throw switch. Then you can use the full power of the circuit in both cases. Example below from a quick google:
Car Charging With an Electric Dryer Outlet

As for socket choices, the mobile connect page on Tesla's site provides a good idea to start with.
Mobile Connector
 
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jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
8,839
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Riverside Co. CA
Seems like it may be a code violation to just tap into that without having something to ensure you will never be able to use both loads at the same time.

I am not an expert, but I am fairly sure that unless there is some sort of mechanism in place to ensure both devices can not be used simultaniously (not just "I wont" but "I cant"), that it would be a code violation, and actually could be dangerous.

Others more knowledgeable can speak to that, but thats what I believe.
 

PhysicsGuy

Member
Apr 16, 2020
98
89
California
I am not an expert, but I am fairly sure that unless there is some sort of mechanism in place to ensure both devices can not be used simultaniously (not just "I wont" but "I cant"), that it would be a code violation, and actually could be dangerous.

Others more knowledgeable can speak to that, but thats what I believe.
I agree. I plan to include an appropriate switch. Hoping to get advice on just how to do that.
 
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PhysicsGuy

Member
Apr 16, 2020
98
89
California
I guess maybe what I need is a NEMA 14-50 outlet box. it looks like my 2018 3 came with a NEMA 14-50 adapter. (pictures attached). Maybe that box could just be on its own nearby post??
 

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PhysicsGuy

Member
Apr 16, 2020
98
89
California
Or, is there such a thing as an adapter from whatever the Tesla wall mounted plug is to a NEMA 14-50?? That would be the easiest and would alleviate concerns about using both at once.
 

stopcrazypp

Well-Known Member
Dec 8, 2007
10,203
5,108
Or, is there such a thing as an adapter from whatever the Tesla wall mounted plug is to a NEMA 14-50?? That would be the easiest and would alleviate concerns about using both at once.
Tesla use to sell a Wall Connector with a 14-50 plug on the end, but they no longer do.
Tesla launches new Wall Connector with NEMA 14-50 plug - Electrek

That doesn't help you much however as you have a hardwired unit. Unless you mean removing that and replacing with a 14-50 socket. Or you need to find someone to add a 14-50 plug to your hardwired unit, although not sure the safety/code implications of that (you need to make sure the unit is dialed down to the same limits as a 14-50 plug).

If you want to buy a Wall Connector unit with the 14-50 plug already attached, you would either have to find it used or buy a mobile connector or a third party J1772 EVSE with 14-50 plug and use a J1772 adapter (included with your car or you can buy a spare).

Closest thing available today is Corded Mobile connector with 14-50 connector (allows 40A vs 32A of the one that can switch adapters):
Corded Mobile Connector

Or third party, something like this:
40A Level 2 EVSE HCS-50P with NEMA 14-50 | ClipperCreek
used with adapter:
SAE J1772 Charging Adapter
 
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leonar40

Member
Jan 6, 2021
244
121
Bloomington, IN
Ya, it's too bad they hard wired it in. My wall charger is connected with a 14-50, so I could technically just split it if I wanted to, although I don't think I'd ever do that. It would not be very expensive to ask an electrician to convert it from hard wired to a 14-50 plug. Then what you do after that is up to you...
 

user212_nr

Active Member
Aug 26, 2019
1,407
744
US
I have a wall mounted connector that can go up to 40 amps. (See picture below). For weird reasons that I can explain (basically distance related) I would like to be able to tap into that safely to get ordinary 240 volts with some sort of appropriate NEMA plug that I can plug into with a good 240 volt extension cord. I would be happy getting 20 amps out of that (and only use it when the wall mounted connector is not in use). Does that sound like a reasonable endeavor? What would that tend to involve? Would love to hear from experts here.
Also, what NEMA would you suggest for the plug I have installed and the 25 to 40 ft extension cord I plan to buy and use? What would be compatible with the onboard charging stuff from Tesla? Thanks a lot.

PS. This would be a dry weather only option. I would not expect to be able to use the extension cord option in the rain.

Legal disclaimer: DIY electrical work requires "permitting" in most city jurisdictions and while most don't bother with them, there are insurance ramifications, etc

Looks like the way your wall connector is mounted doesn't allow much space for a NEMA weatherpoof box to be installed. You can certainly move it up or try to cram one in there. You can hire an electrician or "learn the work yourself" with the help of some on this forum and other resources.

I guess maybe what I need is a NEMA 14-50 outlet box. it looks like my 2018 3 came with a NEMA 14-50 adapter. (pictures attached). Maybe that box could just be on its own nearby post??

https://www.amazon.com/Talon-LGP1S-...ld=1&keywords=14-50+box&qid=1613189900&sr=8-3
https://www.amazon.com/Coleman-Cabl...&keywords=14-50+pigtail&qid=1613189934&sr=8-1

You need also to seal the connection into your wall connector so that there is no air leakage. Maybe some spray foam.

https://www.amazon.com/GREAT-STUFF-Cracks-Insulating-Sealant/dp/B0002YX98O/ref=sr_1_1_sspa
 
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PhysicsGuy

Member
Apr 16, 2020
98
89
California
Tesla use to sell a Wall Connector with a 14-50 plug on the end, but they no longer do.
Tesla launches new Wall Connector with NEMA 14-50 plug - Electrek

That doesn't help you much however as you have a hardwired unit. Unless you mean removing that and replacing with a 14-50 socket. Or you need to find someone to add a 14-50 plug to your hardwired unit, although not sure the safety/code implications of that (you need to make sure the unit is dialed down to the same limits as a 14-50 plug).

If you want to buy a Wall Connector unit with the 14-50 plug already attached, you would either have to find it used or buy a mobile connector or a third party J1772 EVSE with 14-50 plug and use a J1772 adapter (included with your car or you can buy a spare).

Closest thing available today is Corded Mobile connector with 14-50 connector (allows 40A vs 32A of the one that can switch adapters):
Corded Mobile Connector

Or third party, something like this:
40A Level 2 EVSE HCS-50P with NEMA 14-50 | ClipperCreek
used with adapter:
SAE J1772 Charging Adapter
Actually what I am asking in this part is a little different from that. I like the wall connector and plan to use it just as it is about 80% of the time. What I was asking is: Is there an adapter such that one can plug the wall connector into it and adapt it to a 14-50 at the other end. Adapting from the Tesla proprietary wall connector plug to a female 14-50 (into which I can plug an extension cord when needed)? (I am thinking that this is a long-shot and would involve a serious hack partly because of the way in which the car communicates with the wall mounted connector??)

(That adapter is something I would use only when another vehicle (Scamp) is occupying the driveway.)
 
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stopcrazypp

Well-Known Member
Dec 8, 2007
10,203
5,108
Actually what I am asking in this part is a little different from that. I like the wall connector and plan to use it just as it is about 80% of the time. What I was asking is: Is there an adapter such that one can plug the mobile connector into it and adapt it to a 14-50 at the other end. Adapting from the Tesla proprietary wall connector plug to a female 14-50 (into which I can plug an extension cord when needed)?

(That adapter is something I would use only when another vehicle (Scamp) is occupying the driveway.)
Unfortunately given the Tesla Wall Connector (like all EVSEs) does a handshake before providing power, you would need a box that has some smarts in it (basically fool the Wall connector into thinking it was plugged into a car). A "dumb" connector that just converted the electrical connections to 14-50 would not work. I doubt anyone sells a box like that, especially not with Tesla's proprietary socket.

The closest thing I could find that might work perfectly for your application (you are just trying to get some extra length), is this extension with the Tesla proprietary connector. However, the release had been delayed due to covid.
ELONG™ Extension Cable compatible with Tesla vehicles
They also had a service that could extend your cord permanently, but also they suspended that.
Tesla UMC extension

The only other alternative is to use a Tesla socket to J1772 adapter:
https://www.amazon.com/Lectron-Tesla-Charger-J1772-Adapter/dp/B07V7V2QT8
Then use a 20ft J1772 Extension cable (also 40ft available):
https://www.amazon.com/Lectron-J1772-Extension-Compatible-Chargers/dp/B0821FCF7P/
Then use the J1772 adapter included with your Tesla to connect to your Tesla.
SAE J1772 Charging Adapter
However, not sure if the Wall Connector can still function properly through such a long cable and after those adapters.
 

PhysicsGuy

Member
Apr 16, 2020
98
89
California
Unfortunately given the Tesla Wall Connector (like all EVSEs) does a handshake before providing power, you would need a box that has some smarts in it (basically fool the Wall connector into thinking it was plugged into a car). A "dumb" connector that just converted the electrical connections to 14-50 would not work. I doubt anyone sells a box like that, especially not with Tesla's proprietary socket.

The closest thing I could find that might work perfectly for your application (you are just trying to get some extra length), is this extension with the Tesla proprietary connector. However, the release had been delayed due to covid.
ELONG™ Extension Cable compatible with Tesla vehicles
They also had a service that could extend your cord permanently, but also they suspended that.
Tesla UMC extension

The only other alternative is to use a Tesla socket to J1772 adapter:
https://www.amazon.com/Lectron-Tesla-Charger-J1772-Adapter/dp/B07V7V2QT8
Then use a 20ft J1772 Extension cable (also 40ft available):
https://www.amazon.com/Lectron-J1772-Extension-Compatible-Chargers/dp/B0821FCF7P/
Then use the J1772 adapter included with your Tesla to connect to your Tesla.
SAE J1772 Charging Adapter
However, not sure if the Wall Connector can still function properly through such a long cable and after those adapters.
Thanks a lot. That makes a lot of sense. I am thinking the best thing is to mount a 14-50 receptacle and share the circuit (maybe with a double throw switch) as you suggested earlier. I am thinking it might involve a foot or two of conduit to have room to mount the 14-50.
 

wws

Member
Aug 11, 2014
958
975
Northern California
There are some products that do sort of what you want at evseadapters - provided it is a 240V ONLY application. Combine with a TeslaTap or JDapter, and it could all work. For example the following does J1772->NEMA 6-50:

J1772 to NEMA 6-50 Adapter – EVSE Adapters

If you also need 120V, you are out of luck unless there is a voltage transformer included. But it looks like they are starting to offer one of those as well:

EV Charger Power Converter – EVSE Adapters
 

stopcrazypp

Well-Known Member
Dec 8, 2007
10,203
5,108
A 14-50 receptacle has to be on a dedicated circuit which cannot be shared with anything else.
If this is true, @PhysicsGuy is better off modifying the unit to use a 14-50 pigtail instead and install a 14-50 box (making it the same as the 14-50 EVSEs out there). Or maybe explore using that J1772 to 6-50 adapter linked. Disclaimer that I'm not familiar with the code, just that common sense says that there must be provisions to ensure that nothing else can be energized at the same time as EVSE on the same circuit (which I presume that part about dedicated circuit is mainly concerned about).
 
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Rocky_H

Well-Known Member
Feb 19, 2015
6,270
7,322
Boise, ID
Is there an adapter such that one can plug the wall connector into it and adapt it to a 14-50 at the other end. Adapting from the Tesla proprietary wall connector plug to a female 14-50 (into which I can plug an extension cord when needed)? (I am thinking that this is a long-shot and would involve a serious hack partly because of the way in which the car communicates with the wall mounted connector??)
I was going to say no, but...
There are some products that do sort of what you want at evseadapters - provided it is a 240V ONLY application. Combine with a TeslaTap or JDapter, and it could all work. For example the following does J1772->NEMA 6-50:

J1772 to NEMA 6-50 Adapter – EVSE Adapters
That's crazy--I didn't know that existed. So if you want to get really hokey, you could buy the Tesla to J1772 adapter, which is a couple hundred bucks, and then this thing, and then the Tesla 6-50 plug, but it's getting pretty ridiculous at that point.

A 14-50 receptacle has to be on a dedicated circuit which cannot be shared with anything else.
Well, that is close but not quite. 14-50 outlets in general? No. But the new section of NEC about electric vehicle charging does say that circuits to be used for EV charging do need to be dedicated.

@PhysicsGuy Now, there are a couple of things you could do that would make this dedicated, but they would all need to be farther upstream of your wall connector. The A/B throw switch kind of thing can cover that "dedicated" requirement because it does ensure only one thing can be connected at a time. So you would have to interrupt the line before the wall connector to put in that switch and a branch to some kind of outlet.

Or a slightly different idea is to just put in a subpanel that splits this into two smaller circuits that can both be on all the time.
 
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davewill

Active Member
Feb 5, 2014
1,825
1,975
San Diego, CA, US
Yeah I knew about the J1772 to 6-50 thing. If you enquire at EVSEadapters, they might be willing to make a Tesla one. It won't be cheap. Depending on where your panel is, it might be nearly the same price as having another 240v circuit put in.

Reminds me of an RV people used to complain about on the LEAF forum that camped out (they essentially lived there) at one of the free charging stations up in NoCal. They had cobbled together some sort of adapter like that, and were running their RV off of it. They would have needed a transformer for 120v stuff, but in this day and age, a lot of stuff has 100-250v AC adapters, so they could have just done that, plus using the juice to keep their 12v system charged up and running.
 
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dmurphy

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Dec 7, 2018
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New Jersey - Morris County
Reminds me of an RV people used to complain about on the LEAF forum that camped out (they essentially lived there) at one of the free charging stations up in NoCal. They had cobbled together some sort of adapter like that, and were running their RV off of it. They would have needed a transformer for 120v stuff, but in this day and age, a lot of stuff has 100-250v AC adapters, so they could have just done that, plus using the juice to keep their 12v system charged up and running.

Most (all?) RVs with a 50a/240V configuration already have a NEMA 14-50 plug. That means two hots, a neutral and a ground. No need for any kind of a transformer (for the AC load) - their power center functions just like your breaker panel at home - two 120V bus bars.

Very simply, one of these: J1772 to NEMA 14-50 Adapter – EVSE Adapters
and their entire RV has power - both AC and DC systems, since the 12V DC converter is onboard already. No extra work needed to hookup to the J1772.

All they're looking for decent amperage, 240V -- and a J1772 provides exactly that.

Now, depending on the EVSE they're abusing here, they could certainly overdraw amperage and cause a real problem -- running two A/C units along with a microwave, fridge and the other electronics aboard... If the EV is equipped with a 14-50 plug, it should draw 40A maximum. Depending on the EVSE, that could be too high.
 
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Rocky_H

Well-Known Member
Feb 19, 2015
6,270
7,322
Boise, ID
Most (all?) RVs with a 50a/240V configuration already have a NEMA 14-50 plug. That means two hots, a neutral and a ground. No need for any kind of a transformer (for the AC load) - their power center functions just like your breaker panel at home - two 120V bus bars.

Very simply, one of these: J1772 to NEMA 14-50 Adapter – EVSE Adapters
and their entire RV has power - both AC and DC systems, since the 12V DC converter is onboard already. No extra work needed to hookup to the J1772.
No, that's not how that works. They would need the transformer to get 120V.
That means two hots, a neutral and a ground.
Exactly. The RV is trying to provide all of its 120V loads using a hot and the neutral to complete the circuit. The J1772 supplying this whole situation through that adapter is only the two hot lines that are 240V apart from each other (or 208V), and there is no neutral provided there. And I would be horrified to think if whoever made that adapter tried to use a hot to ground as a legitimate current path for the circuits. That would be dangerous.
 

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