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Charging with a 3 prong dryer outlet?

Can anyone tell me what kind of adapter and extension cord I would need to use this spare dryer outlet to charge a LR MY? Thanks!!

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FlatSix911

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Jun 15, 2015
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Jeff N

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Oct 31, 2011
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This is probably what you need. This adapter plugs into your 10-50 outlet and converts it into a “14-50” outlet which can be used with a Tesla or other EVSE that can plug into a 14-50.

This conversion adapter should only be used for this purpose since it does not really provide a separate neutral as well as ground. Use it for car charging only.

 

Sophias_dad

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Else you can overload wires, with fire risk.
In theory if the installer of the wires was doing their job correctly, there should be no fire risk. The breaker >should< be limited by the wire size and if you draw enough current to make the wires hazardous, the breaker should trip.

Even checking the breaker is not a guarantee there isn't a fire risk. 'Professionals' might have a bad day, a homeowner could have done the install themselves and put a 50 amp breaker where a 30 amp belongs, and so on.

Were it my home I'd check the wire gauge as well, and verify the termination points of the wiring is good and tight. This goes extra-double for if OP is going to use any form of extension cord or adapter on the outlet end because the UMC monitors the plug temperature, but if its a foot(or 25') away from the outlet, that measurement will not work at all.
 

Rocky_H

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Feb 19, 2015
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Have a 30 amp dryer at my vacation home. Dropped amp in the vehicle to 24 amps and plugged it in. Charged at 21 mi/hr. Worked perfectly
I'm not sure if you know this yet, but as long as you are just using the regular Tesla equipment, with one of their adapters for that dryer outlet attached to the mobile charging cable, you do not need to manually adjust current. The adapters have a chip in them that signals the proper amount of amps for that plug type, so it would have automatically set it for 24A anyway.
 
I'm not sure if you know this yet, but as long as you are just using the regular Tesla equipment, with one of their adapters for that dryer outlet attached to the mobile charging cable, you do not need to manually adjust current. The adapters have a chip in them that signals the proper amount of amps for that plug type, so it would have automatically set it for 24A anyway.
Ya I was in a hurry to buy one and purchased this one from Amazon https://www.amazon.com/dp/B00STD8S7C?psc=1&ref=ppx_pop_dt_b_asin_image after further research I realized Tesla had one. I have not tried it yet but I expect it will lower voltage as you stated. Now I have two but that's ok
 

Rocky_H

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Feb 19, 2015
8,365
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Boise, ID
Ya I was in a hurry to buy one and purchased this one from Amazon https://www.amazon.com/dp/B00STD8S7C?psc=1&ref=ppx_pop_dt_b_asin_image after further research I realized Tesla had one. I have not tried it yet but I expect it will lower voltage as you stated. Now I have two but that's ok
It's not adjusting voltage, by the way; it's amps. But no, that will not automatically signal the right amperage. The signaling is from a chip in the Tesla adapters. That cable you bought is just a cable that lets you plug into a 10-30 outlet, but then makes you use your Tesla 14-50 plug. That 14-50 Tesla plug will think that it is a 50A outlet type, and will signal the car to use the max that the mobile charging cable can do, 32A, which will overdraw that circuit and trip the breaker (hopefully). We used to have to do that stuff years ago, when Tesla had a very slim selection of adapters, and we had to adapt almost everything to 14-50, and I do actually have a cable just like that one from back then, but it's not a very good solution for now.
 
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Hello. I have a similar question/issue. My garage water heater outlet installed by previous home owner) is labeled a 10-30R (on it's own 30Amp breaker) so I bought the Tesla 10-30 adapter for my mobile charger. It starts charging fine but stops charging with a code of 4 red light blinks whenever the microwave is used (different circuit breaker). After looking at the chart above, I have a feeling the charger doesn't like this connection because it doesn't have a ground connection.

My neighbor knows a little about electrical and suggested changing the dryer outlet to a 4 prong 14-30R connection since the current outlet has a 4th wire to support the it. (Ground wire sits in back of the box currently). I would need to purchase a Tesla 14-30 connection instead of the 10-30 I originally bought.

Wondering if anyone else experienced this and if they attempted this solution with any success.

Thanks.
 
Hello. I have a similar question/issue. My garage water heater outlet installed by previous home owner) is labeled a 10-30R (on it's own 30Amp breaker) so I bought the Tesla 10-30 adapter for my mobile charger. It starts charging fine but stops charging with a code of 4 red light blinks whenever the microwave is used (different circuit breaker). After looking at the chart above, I have a feeling the charger doesn't like this connection because it doesn't have a ground connection.

My neighbor knows a little about electrical and suggested changing the dryer outlet to a 4 prong 14-30R connection since the current outlet has a 4th wire to support the it. (Ground wire sits in back of the box currently). I would need to purchase a Tesla 14-30 connection instead of the 10-30 I originally bought.

Wondering if anyone else experienced this and if they attempted this solution with any success.

Thanks.
We have a condo in Palm Beach County and hot water heaters that are plugged into an 240v electrical outlet no longer meet code. Our hot water heater is hard wired to a on/off switch that we turn off when we are not there.
You didn't mention what your main breaker capacity is, but I would suggest that you have a licensed electrician do a proper EV installation for you.
Get a few quotes from Tesla recommended electricians.
Just my $.02
 
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Rocky_H

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Feb 19, 2015
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Boise, ID
My neighbor knows a little about electrical and suggested changing the dryer outlet to a 4 prong 14-30R connection since the current outlet has a 4th wire to support the it. (Ground wire sits in back of the box currently). I would need to purchase a Tesla 14-30 connection instead of the 10-30 I originally bought.

Wondering if anyone else experienced this and if they attempted this solution with any success.
Oh, well that doesn't really need any consultation. That is a perfect solution that will absolutely work! If the extra ground wire is in there, then it can easily be converted to a 14-30.

The Tesla plug needs to use something as if it is a ground. On the 10-30, it's a little hand waving, where they map the "ground" on the Tesla charging plug to that slot in the 10-30 outlet that is actually a neutral. They both should be about at 0 volts, so that normally works fine. But as you found, that neutral bus is used for current return on 120V circuits through the house, so heavy loads on it can bounce that neutral around some above or below 0V, and it upsets the Tesla charging equipment that thinks something is wrong with the supposed "ground".

So yes, switching over to the 14-30 so the Tesla plug can use a real ground as ground that won't have current on it elsewhere in the house's wiring will stabilize that.
 
Oh, well that doesn't really need any consultation. That is a perfect solution that will absolutely work! If the extra ground wire is in there, then it can easily be converted to a 14-30.

The Tesla plug needs to use something as if it is a ground. On the 10-30, it's a little hand waving, where they map the "ground" on the Tesla charging plug to that slot in the 10-30 outlet that is actually a neutral. They both should be about at 0 volts, so that normally works fine. But as you found, that neutral bus is used for current return on 120V circuits through the house, so heavy loads on it can bounce that neutral around some above or below 0V, and it upsets the Tesla charging equipment that thinks something is wrong with the supposed "ground".

So yes, switching over to the 14-30 so the Tesla plug can use a real ground as ground that won't have current on it elsewhere in the house's wiring will stabilize that.
Wow. Thanks for explaining the logic behind that suggestion. I'm more inclined to move forward now.
 

jcanoe

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Oct 2, 2020
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Sophias_dad

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Oh, well that doesn't really need any consultation. That is a perfect solution that will absolutely work! If the extra ground wire is in there, then it can easily be converted to a 14-30.

The Tesla plug needs to use something as if it is a ground. On the 10-30, it's a little hand waving, where they map the "ground" on the Tesla charging plug to that slot in the 10-30 outlet that is actually a neutral. They both should be about at 0 volts, so that normally works fine. But as you found, that neutral bus is used for current return on 120V circuits through the house, so heavy loads on it can bounce that neutral around some above or below 0V, and it upsets the Tesla charging equipment that thinks something is wrong with the supposed "ground".

So yes, switching over to the 14-30 so the Tesla plug can use a real ground as ground that won't have current on it elsewhere in the house's wiring will stabilize that.
Since ground and neutral are linked at the main panel, I would expect that the neutral getting dragged away from 0 volts would simultaneously drag the ground away the same amount. Unless of course the installer did some crazy stuff like piggyback the neutral line into some other 120V circuits along the way.
 

Sophias_dad

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Jul 29, 2018
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Hello. I have a similar question/issue. My garage water heater outlet installed by previous home owner) is labeled a 10-30R (on it's own 30Amp breaker) so I bought the Tesla 10-30 adapter for my mobile charger. It starts charging fine but stops charging with a code of 4 red light blinks whenever the microwave is used (different circuit breaker). After looking at the chart above, I have a feeling the charger doesn't like this connection because it doesn't have a ground connection.

My neighbor knows a little about electrical and suggested changing the dryer outlet to a 4 prong 14-30R connection since the current outlet has a 4th wire to support the it. (Ground wire sits in back of the box currently). I would need to purchase a Tesla 14-30 connection instead of the 10-30 I originally bought.

Wondering if anyone else experienced this and if they attempted this solution with any success.

Thanks.
What does your reported voltage on the car's screen say when its just starting charging(0-5 amps), charging at 24 amps, and charging at 24 amps when the microwave gets turned on? You could be seeing effects of a weak connection, either to your 10-30 outlet, the main power feed to your home(whether that's your meter, your main circuit breaker, or whatever), or even a weak(or overloaded) power pole transformer.
 
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What does your reported voltage on the car's screen say when its just starting charging(0-5 amps), charging at 24 amps, and charging at 24 amps when the microwave gets turned on? You could be seeing effects of a weak connection, either to your 10-30 outlet, the main power feed to your home(whether that's your meter, your main circuit breaker, or whatever), or even a weak(or overloaded) power pole transformer.
So... This evening I went to Home Depot and picked up the 4 prong outlet. While removing the old 3 prong I noticed the wires were slightly loose. I proceeded to change the outlet and made sure it was pretty tight...

Using my neighbors 4 prong 14-30 connector, I plugged in and saw reported voltage jumping between 247 & 248. Once the Amps climbed to 24, the voltage dropped to 241 and seems to dance between 240, 241 & 242.

Never thought to look at the voltage before... What does that mean?

Either way, I tried the microwave again and the car reported charging interrupted and charger is blinking 3 red lights.
 

jcanoe

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Oct 2, 2020
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No green light / 3 flashing red lights - Relay contactor fault. Unplug the Mobile Connector from the vehicle and then plug it back in. Try a different outlet. If the error persists, contact Tesla.

I wouldn't have been so quick to change the 10-30R to the 14-30R unless I knew the ground wire was properly connected at the service panel. I would have tightened the connections on the 10-30R and tried to charge. Rapidly going down a rabbit hole now; no way of knowing where it will end.
 
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