Extension cords: NEMA 14-30, 10-30, 6-50, or 6-20...

[crosssmash60]

On my first trial charging model Y using 240 volts dryer output thru 10-30 to 15-40 adapter was a brief one, lasted about 30 minutes with 32A charging then it suddenly shutoff mostly due to safety issue. I was not able to make it work again even though tried lower form 32A to 12A. However, the next morning I tried again with 12A and it worked then I push up 25A and is still running well. My guess is the 10-30 only output 30A(so is the circuit breaker) and I was pushing to 32A. I also noticed the wires used in the breaker is 10 gauge hence unable to sustain the load of 32A?
So far running at 25A seems solving the issue. My adapter is Flameweld EV Charger.

​

 

[davewill]

If your Flameweld EVSE can't be configured for a 30a circuit, then I don't recommend you use it on one. We generally recommend that people
get the proper 10-30 adapter for the Tesla mobile connector which limits the charging rate to 24a, the correct level for a 30a circuit. Lowering the level in the car is NOT sufficient as there are scenarios where that setting may be ignored, causing the car to revert to it's top charging rate. Overdrawing the circuit can result in overheating or fires, not something to purposely risk.

 

[n2mb_racing]

On my first trial charging model Y using 240 volts dryer output thru 10-30 to 15-40 adapter was a brief one, lasted about 30 minutes with 32A charging then it suddenly shutoff mostly due to safety issue. I was not able to make it work again even though tried lower form 32A to 12A. However, the next morning I tried again with 12A and it worked then I push up 25A and is still running well. My guess is the 10-30 only output 30A(so is the circuit breaker) and I was pushing to 32A. I also noticed the wires used in the breaker is 10 gauge hence unable to sustain the load of 32A?
So far running at 25A seems solving the issue. My adapter is Flameweld EV Charger.

​

Dryer outlets (10-30 and 14-30) are only rated for 24A continuous. Lower the current down to 24A.

 

[crosssmash60]

If your Flameweld EVSE can't be configured for a 30a circuit, then I don't recommend you use it on one. We generally recommend that people
get the proper 10-30 adapter for the Tesla mobile connector which limits the charging rate to 24a, the correct level for a 30a circuit. Lowering the level in the car is NOT sufficient as there are scenarios where that setting may be ignored, causing the car to revert to it's top charging rate. Overdrawing the circuit can result in overheating or fires, not something to purposely risk.

Thank you for your advice, I am planning to hire an electrician to install 14-50 outlet, Using the adapter is just my

Dryer outlets (10-30 and 14-30) are only rated for 24A continuous. Lower the current down to 24A.

Thank you, will do that until new 14-50 outlet is installed.

 

[crosssmash60]

If your Flameweld EVSE can't be configured for a 30a circuit, then I don't recommend you use it on one. We generally recommend that people
get the proper 10-30 adapter for the Tesla mobile connector which limits the charging rate to 24a, the correct level for a 30a circuit. Lowering the level in the car is NOT sufficient as there are scenarios where that setting may be ignored, causing the car to revert to it's top charging rate. Overdrawing the circuit can result in overheating or fires, not something to purposely risk.

Thank you for your advice, I am planning to install 10-50 outlet soon.

 

[Droschke]

My adapter is Flameweld EV Charger.

​

This one?

 

[n2mb_racing]

Thank you for your advice, I am planning to install 10-50 outlet soon.

Another easy option is just buy the Tesla 10-30 UMC plug. I use one and it works fine.

Gen 2 NEMA Adapters

Use a variety of household outlets to charge your Tesla with a Gen 2 NEMA Adapter. Simply attach the appropriate adapter to your Mobile Connector, plug into the corresponding outlet and begin charging. Adapter Max Distance Gained Per Hour of Charge Model S Model 3 Model X Model Y 5-15 3...

shop.tesla.com

 

[Droschke]

I would not use any Non-Tesla adapters unless I know they are internally wired correctly for Tesla charging.

 

[davewill]

Thank you for your advice, I am planning to hire an electrician to install 14-50 outlet, Using the adapter is just my

Thank you, will do that until new 14-50 outlet is installed.

Sure, dialing it down is fine for a short time, as you can check the charging level each time you plug in. Just use 24a, instead of 25a.

Thank you for your advice, I am planning to install 10-50 outlet soon.

10-50s can't be installed on new circuits anymore, so it would have to be a 14-50 or a 6-50.

 

[n2mb_racing]

I would not use any Non-Tesla adapters unless I know they are internally wired correctly for Tesla charging.

Eh. There's not too many ways to wire NEMA adapters. And since our cars only need hot, hot, and ground, none of them are really bad for the car. There is one adapter configuration that doesn't work. It's the generic TT-30 to NEMA 14-50 adapter for campers. It puts both 120V hots on the two UMC hot pins, so the net voltage between them is zero and car won't do anything.

Now, going the other way around, some adapters that do work for Tesla charging can be very dangerous for RV use, since we don't care about the neutral in EV charging, but RV's really do need the neutral.

 

[Droschke]

For the adapter used in this example, on the 14-50 side, what's connected to ground? what's connected to the neutral?

 

[davewill]

For the adapter used in this example, on the 14-50 side, what's connected to ground? what's connected to the neutral?

You connect the 10-30 neutral to the 14-50 ground and leave the 14-50 neutral unconnected (and make double dog sure that you don't use it for anything but EV charging). That's essentially what the Tesla 10-30 adapter does. As long as the 10-30 is wired directly to the main panel, there's no issue.

 

[Droschke]

You connect the 10-30 neutral to the 14-50 ground. That's essentially what the Tesla 10-30 adapter does. As long as the 10-30 is wired directly to the main panel, there's no issue.

Yes, that's the correct connection for Tesla charging. My point was we do not know what these Non-Tesla adapters are wired for and if they are wired correctly for Tesla charging. In fact if the adapter we are discussing is the one I linked above, it says it's for generators, with a picture of a Tesla Model 3 inserted on the side.

 

[crosssmash60]

This one?

Yes, here's the link on Amazon. https://www.amazon.com/dp/B09X1BTD8V?psc=1&ref=ppx_yo2ov_dt_b_product_details
One of the product descriptions:
【EV Charging】Charge your EV with up to 5.76kW (240V 24 Amp) Level 2 EV portable charger, 22 MPH for Model 3 and Model Y, and 15 MPH for Model S and Model X. No need to install an additional charging pile in the garage.
So highest amp is 24 max.

 

[n2mb_racing]

Yes, that's the correct connection for Tesla charging. My point was we do not know what these Non-Tesla adapters are wired for and if they are wired correctly for Tesla charging. In fact if the adapter we are discussing is the one I linked above, it says it's for generators, with a picture of a Tesla Model 3 inserted on the side.

How else could they wire it? Any way they wire it would work for Tesla charging. Bad for RVs, though, no matter what.

 

[Droschke]

How else could they wire it? Any way they wire it would work for Tesla charging. Bad for RVs, though, no matter what.

For Tesla charging:

Does it work if the NEMA 10-30 neutral prong is connected to the NEMA 14-50 neutral prong and the NEMA 14-50 ground is left unconnected?

Is it safe?

 

[n2mb_racing]

For Tesla charging:

Does it work if the NEMA 10-30 neutral prong is connected to the NEMA 14-50 neutral prong and the NEMA 14-50 ground is left unconnected?

Is it safe?

Hmm yeah, interesting one. No, it wouldn't charge. The umc tests if the ground is connected and will refuse to turn on if not connected. It doesn't use the neutral.

The adapter likely connects the 10-30 neutral to both the ground and neutral for it to work.

 

[davewill]

How else could they wire it? Any way they wire it would work for Tesla charging. Bad for RVs, though, no matter what.

Yeah, I don't see any way you could safely adapt a 10-30 for RV use. An RV needs both the neutral and the ground. Tying them together leaves you with a ground that can shock you, and leaving it ungrounded is no good. Even worse if you try to use a EV adapter that leaves neutral disconnected. Current will flow from one hot through an appliance into the neutral bus, then through a different appliance into the other hot. The neutral bus in the RV will float somewhere between the two hots, depending on the loads. You'll have some appliances trying to run on too much voltage and others trying to run on too little.

 

[Eric33432]

I purchased this NEMA 14-30P to NEMA 10-30R adapter:

https://www.amazon.com/gp/product/B07YD9HWD4/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&th=1

I toned it out, and the ground prong on the 14-30 end is connected to nothing. The neutral is carried through from the 14-30P to the neutral on the 10-30R on this NEMA adapter cable. Which is what I expected.

Proper wiring of a NEMA 10-30 receptacle for a dryer, back when they were allowed, required the neutral to be wired to the neutral bar , which is the same as the ground bar if the panel is Service Equipment, but if being wired to a sub panel is separate from the ground bar.

This may be why at least some NEMA 10-30R dryer outlets that I have seen are wired with 10/3, which use the white wire for the neutral and the ground wire not connected to any of the pins of the outlet, but is connected to the box if it is a metal box. Which is great if you want to upgrade the dryer receptacle to a 4 prong 14-50 in a pre-1996 house; all you have to do is change the receptacle.

It is done that way because a 10-30 is a 120/240 volt device, and originally, before EV's were invented, most devices designed to plug into a 10-30R expect a neutral on the neutral connection, not a ground.

The Tesla 10-30 cable for the Mobile Connector really can't tell any difference between the neutral and the ground; however the Tesla engineers are well aware that a NEMA 10-30 receptacle is wired with a neutral, not a ground, and would not have provided this adapter if it would be dangerous to use it.

BTW, I purchased this 50 foot long extension cord:

https://www.amazon.com/gp/product/B08LKKTJ5R/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&th=1

made with #10 wire, that has the NEMA 10-30 plug and receptacle so I can charge from dryer receptacles when traveling to vacation homes and friends/family, and the adapter allows me to plug in and use the same cord when the property is equipped with a NEMA 14-30 dryer receptacle.

 

[Eric33432]

Above I wrote:

"Which is great if you want to upgrade the dryer receptacle to a 4 prong 14-50 in a pre-1996 house; all you have to do is change the receptacle."

I should have written:

"Which is great if you want to upgrade the dryer receptacle to a 4 prong 14-30 in a pre-1996 house; all you have to do is change the receptacle."