Home Charging Question on Using Electric Dryer Outlet 10-30A

[posity]

All of us EV owners need to be in the habit of checking the breaker size whenever we plug into a receptacle 'in the wild', then adjust the screen amps to no more than 80% of that breaker size. We need to make a habit of understanding exactly what we are plugging into and adjust our EV to match the breaker. Blindly plugging in our EV and walking away, without knowing the breaker size, is a recipe to be drawing more current than the breaker can handle. We all need to be aware that code allowed (allows) undersize breakers on a receptacle so there is ALWAYS the possibility that a 50A receptacle (14-50, 6-50 or 10-50) can be on any size breaker (30A, 40A, 50A - but could even be smaller)! Code does not allow a breaker to be larger than the receptacle's rating, but does allow a breaker to be smaller.

So I know folks mean well by saying that a dryer plug SHOULD be changed out to a 14-30 (or leave an existing 6-30 or 10-30) plug, but the reality is that any size receptacle 30A or larger was (is) legal for that dryer. Changing out the receptacle and using the correct Tesla adapter will ensure we automatically don't draw too much current, but my point here is that we ALWAYS have to think about the breaker size anyhow (and adjust the current on your Tesla's screen) - it is just a habit every EV owner needs to develop. Plugging in your EV is not like plugging in a toaster: we need to do a little (breaker size and wire size) investigation whenever we plug in our EVs.

For me, I also try to check the wire size connected to the breaker (if visible) since there are so many installations that get the wire size detail wrong too. If I see 10 AWG wire, then I use a 24A setting on the Tesla (10 AWG wire should have a 30A breaker). If I see 8 AWG or larger, then the Tesla max 32A setting does not need to be modified.

 

[Big Earl]

The setting is remembered for that geolocation. The setting you choose survives reboots and software updates.

Software update 2019.32 just reset the charging limit at my home location back to the maximum provided by my wall connector. I had it dialed down.

 

[Juleeh222]

Hello! My car garage electric clothes dryer has the old straight-pin 10-30 plug. Through Tesla, I ordered and received a NEMA 10-30 adapter (the one with that 2 straight and 1 "L" pin). I would like to use my existing 220V 30A wall socket and plan to plug (unplug) my Tesla portable adapter into my dryer wall socket at nights. Can you tell me exactly what adapter piece I would need to buy, so that I can make this happen (safely)? I'm trying to avoid having to spend more money on a Tesla Wall Connector and hiring an electrician, just to add another garage outlet (since I already have an existing 220V wall socket behind my electric dryer). Thank you thank you!!

Hi I realize this is an old post but I have a similar question:
I have a 10-30 dryer that I want to connect as well. Is it okay to buy a non Tesla adapter? What are the repercussions? I also will need an extension cord to reach my car, I have seen those on Amazon. Just don't want to blow up my house. Thanks.

 

[srs5694]

Hi I realize this is an old post but I have a similar question:
I have a 10-30 dryer that I want to connect as well. Is it okay to buy a non Tesla adapter? What are the repercussions? I also will need an extension cord to reach my car, I have seen those on Amazon. Just don't want to blow up my house. Thanks.

Tesla sells a NEMA 10-30 adapter for $35. It looks like it may be out of stock right now, but my general impression is that these adapters don't go out of stock for long periods of time, so it's probably better to wait than to buy a third-party adapter. I know that third-party adapters do exist, but they tend to cost more. In theory, they should function just like a Tesla adapter, but who knows? When Some Random Tinkerer reverse-engineers a device and starts selling clones, that work might or might not be done competently. You as a consumer have no way of knowing, and that state of a lack of knowledge applies to most of us here. (I think that one person who sells such adapters posts here from time to time.)

As to sharing one outlet between a dryer and an EV, plugging and unplugging the devices frequently is inadvisable. The 240v plugs used in homes tend to be designed to last just a few plug-unplug cycles, so you'd probably end up needing a new plug in a few months if you went this route. (In fact, there's a thread here that describes differences between several brands of NEMA 14-50 outlet.) Instead, look into the Dryer Buddy, which is a device intended to help with this task specifically. I think the "Plus Auto" version is the most flexible. (I think there's a page describing the variants somewhere on the site, but I don't see it in a quick search, and I'm not intimately familiar with the product differences.)

It's best to avoid extension cords if possible, but if you must use one, be sure it's of high quality, not some cheap thing put together from sub-standard parts.

Instead of investing in a Dryer Buddy and extension cord, you might look into what it would cost to install a NEMA 14-50 outlet closer to your car's charge port. The cost might not be much more than the combination of Dryer Buddy plus an extension cord, and the result will be more convenient and possibly safer.

 

[Glamisduner]

All of us EV owners need to be in the habit of checking the breaker size whenever we plug into a receptacle 'in the wild', then adjust the screen amps to no more than 80% of that breaker size. We need to make a habit of understanding exactly what we are plugging into and adjust our EV to match the breaker. Blindly plugging in our EV and walking away, without knowing the breaker size, is a recipe to be drawing more current than the breaker can handle. We all need to be aware that code allowed (allows) undersize breakers on a receptacle so there is ALWAYS the possibility that a 50A receptacle (14-50, 6-50 or 10-50) can be on any size breaker (30A, 40A, 50A - but could even be smaller)! Code does not allow a breaker to be larger than the receptacle's rating, but does allow a breaker to be smaller.

So I know folks mean well by saying that a dryer plug SHOULD be changed out to a 14-30 (or leave an existing 6-30 or 10-30) plug, but the reality is that any size receptacle 30A or larger was (is) legal for that dryer. Changing out the receptacle and using the correct Tesla adapter will ensure we automatically don't draw too much current, but my point here is that we ALWAYS have to think about the breaker size anyhow (and adjust the current on your Tesla's screen) - it is just a habit every EV owner needs to develop. Plugging in your EV is not like plugging in a toaster: we need to do a little (breaker size and wire size) investigation whenever we plug in our EVs.

For me, I also try to check the wire size connected to the breaker (if visible) since there are so many installations that get the wire size detail wrong too. If I see 10 AWG wire, then I use a 24A setting on the Tesla (10 AWG wire should have a 30A breaker). If I see 8 AWG or larger, then the Tesla max 32A setting does not need to be modified.

Tesla will Max out 24amps on a 14-30 or a 10-30. 32 amps will be Max with the stock charger on a 14-50.

 

[Dr. J]

Hi I realize this is an old post but I have a similar question:
I have a 10-30 dryer that I want to connect as well. Is it okay to buy a non Tesla adapter? What are the repercussions? I also will need an extension cord to reach my car, I have seen those on Amazon. Just don't want to blow up my house. Thanks.

I used a Tesla adapter and heavy duty extension cord to charge my car off the old dryer outlet for a few months before my garage with NEMA 14-50 outlets was completed. I found if I left the extension cord plugged in (which it still is) to the wall outlet, I could easily swap out the dryer cord and Tesla cable as needed. A happy side effect is that it's much easier to pull my dryer out of the tight utility closet for maintenance with the extension cord. So far, nothing bad has happened. YMMV.

 

[Juleeh222]

Hi I realize this is an old post but I have a similar question:
I have a 10-30 dryer that I want to connect as well. Is it okay to buy a non Tesla adapter? What are the repercussions? I also will need an extension cord to reach my car, I have seen those on Amazon. Just don't want to blow up my house. Thanks.

Tesla sells a NEMA 10-30 adapter for $35. It looks like it may be out of stock right now, but my general impression is that these adapters don't go out of stock for long periods of time, so it's probably better to wait than to buy a third-party adapter. I know that third-party adapters do exist, but they tend to cost more. In theory, they should function just like a Tesla adapter, but who knows? When Some Random Tinkerer reverse-engineers a device and starts selling clones, that work might or might not be done competently. You as a consumer have no way of knowing, and that state of a lack of knowledge applies to most of us here. (I think that one person who sells such adapters posts here from time to time.)

As to sharing one outlet between a dryer and an EV, plugging and unplugging the devices frequently is inadvisable. The 240v plugs used in homes tend to be designed to last just a few plug-unplug cycles, so you'd probably end up needing a new plug in a few months if you went this route. (In fact, there's a thread here that describes differences between several brands of NEMA 14-50 outlet.) Instead, look into the Dryer Buddy, which is a device intended to help with this task specifically. I think the "Plus Auto" version is the most flexible. (I think there's a page describing the variants somewhere on the site, but I don't see it in a quick search, and I'm not intimately familiar with the product differences.)

It's best to avoid extension cords if possible, but if you must use one, be sure it's of high quality, not some cheap thing put together from sub-standard parts.

Instead of investing in a Dryer Buddy and extension cord, you might look into what it would cost to install a NEMA 14-50 outlet closer to your car's charge port. The cost might not be much more than the combination of Dryer Buddy plus an extension cord, and the result will be more convenient and possibly safer.

Thanks for your reply. I am on the email list for when the adapter is available and saw one on eBay.
Good advice on the plug... I read the thread. At this point, it is not possible to add anything to our breaker or get a sub panel so I am stuck with a 110 plug in at home or stopping at an inconvenient Supercharger station on a regular basis.

 

[Juleeh222]

Tesla will Max out 24amps on a 14-30 or a 10-30. 32 amps will be Max with the stock charger on a 14-50.

Hi, May I PM you in some way? We live close by each other. I am also in Escondido.

 

[posity]

Tesla will Max out 24amps on a 14-30 or a 10-30. 32 amps will be Max with the stock charger on a 14-50.

It appears you may have missed the point I was trying to make. You WILL find many 14-50 receptacles on breakers that are less than 50A, including 40A and 30A (all of which are legal on a 14-50 receptacle). I have twice found 14-50 (or 6-50 or 10-50) receptacles on 30A breakers at friend's homes (at their dryers). So if the 14-50 (or 6-50 or 10-50) you are plugging into is on a 30A breaker, you will need to manually adjust the current down to 24A on your Tesla since the Tesla has no way of knowing breaker size: it only knows the size of the Tesla adapter. So you MUST be in the habit of checking breaker size when plugging into outlets 'in the wild' since there are so many legal (not to mention illegal) combinations of receptacles and breakers installed.

 

[Dmagyar]

It appears you may have missed the point I was trying to make. You WILL find many 14-50 receptacles on breakers that are less than 50A, including 40A and 30A (all of which are legal on a 14-50 receptacle). I have twice found 14-50 (or 6-50 or 10-50) receptacles on 30A breakers at friend's homes (at their dryers). So if the 14-50 (or 6-50 or 10-50) you are plugging into is on a 30A breaker, you will need to manually adjust the current down to 24A on your Tesla since the Tesla has no way of knowing breaker size: it only knows the size of the Tesla adapter. So you MUST be in the habit of checking breaker size when plugging into outlets 'in the wild' since there are so many legal (not to mention illegal) combinations of receptacles and breakers installed.

Afraid that this nuance is over most peoples grasp of what is going on...

 

[ralph142]

Afraid that this nuance is over most peoples grasp of what is going on...

Indeed, all most people know is that there is a dryer, or range, or ac plugged in. Me too, then I got an ev...

 

[appleguru]

It appears you may have missed the point I was trying to make. You WILL find many 14-50 receptacles on breakers that are less than 50A, including 40A and 30A (all of which are legal on a 14-50 receptacle). I have twice found 14-50 (or 6-50 or 10-50) receptacles on 30A breakers at friend's homes (at their dryers). So if the 14-50 (or 6-50 or 10-50) you are plugging into is on a 30A breaker, you will need to manually adjust the current down to 24A on your Tesla since the Tesla has no way of knowing breaker size: it only knows the size of the Tesla adapter. So you MUST be in the habit of checking breaker size when plugging into outlets 'in the wild' since there are so many legal (not to mention illegal) combinations of receptacles and breakers installed.

Assuming the wire is properly sized for the breaker (or greater), then this isn't really an issue. You try to draw 40A from a 30A breaker, the breaker will trip. Then, when you go to turn it back on, you'll see that it is only 30A and adjust your current down appropriately.

If the wire is too small for the breaker, that's potentially dangerous, is a code violation, and should get remedied ASAP.

 

[posity]

Assuming the wire is properly sized for the breaker (or greater), then this isn't really an issue. You try to draw 40A from a 30A breaker, the breaker will trip. Then, when you go to turn it back on, you'll see that it is only 30A and adjust your current down appropriately.

Truly terrible advice. You should never attach a device whose load is rated higher than the breaker and rely on the breaker to detect it. Ever heard of Federal Pacific breakers? (thousands of fires caused by this one brand alone) The Tesla is a worst case scenario since it draws 32A which is very close to the 30A (within 10%) and may take a very long time for the breaker to trip - or not trip at all. NEC is very clear that a constant load device should never draw more than 80% of the breaker rating. This is indeed a safety issue and should not be casually dismissed.

 

[Dmagyar]

Truly terrible advice. You should never attach a device whose load is rated higher than the breaker and rely on the breaker to detect it. Ever heard of Federal Pacific breakers? (thousands of fires caused by this one brand alone) The Tesla is a worst case scenario since it draws 32A which is very close to the 30A (within 10%) and may take a very long time for the breaker to trip - or not trip at all. NEC is very clear that a constant load device should never draw more than 80% of the breaker rating. This is indeed a safety issue and should not be casually dismissed.

Good point, we all test all our home breakers every year, as we're supposed to, right? Some breakers might not trip at all. But surely the average homeowner doesn't have the equipment to check, nor the inclination to do so in the first place, so a moot point.
With the current state of electrical understanding in the general public, it's indeed a wonder that more homes don't burn down every day. When the guy stocking the shelves at HD becomes the de facto electrical expert, we're all in trouble.

 

[wws]

It appears you may have missed the point I was trying to make. You WILL find many 14-50 receptacles on breakers that are less than 50A, including 40A and 30A (all of which are legal on a 14-50 receptacle).

It is legal (i.e., there is an exception stated in the NEC) to use a 50 amp receptacle on a 40 amp circuit. But on a 30 amp circuit, one must use a 30 amp receptacle.

I have twice found 14-50 (or 6-50 or 10-50) receptacles on 30A breakers at friend's homes (at their dryers). So if the 14-50 (or 6-50 or 10-50) you are plugging into is on a 30A breaker, you will need to manually adjust the current down to 24A on your Tesla since the Tesla has no way of knowing breaker size: it only knows the size of the Tesla adapter. So you MUST be in the habit of checking breaker size when plugging into outlets 'in the wild' since there are so many legal (not to mention illegal) combinations of receptacles and breakers installed.

Such installations are not code-compliant.

Still... it is a good idea to check the breaker.

 

[Rocky_H]

It is legal (i.e., there is an exception stated in the NEC) to use a 50 amp receptacle on a 40 amp circuit. But on a 30 amp circuit, one must use a 30 amp receptacle.



Such installations are not code-compliant.

Still... it is a good idea to check the breaker.

I really wish you were correct, but not so. Unfortunately the requirement is just the breaker is no higher than the receptacle type. And so it is allowed by NEC to have 50A receptacles on 20 or 30 amp circuit breakers. It is kind of dumb to do it that way, but not forbidden.

 

[wws]

I really wish you were correct, but not so. Unfortunately the requirement is just the breaker is no higher than the receptacle type. And so it is allowed by NEC to have 50A receptacles on 20 or 30 amp circuit breakers. It is kind of dumb to do it that way, but not forbidden.

NEC Table 210-21(b)(3) and Table 210-24 are pretty explicit as far as which receptacle ratings are to be used on various capacity circuits. (At least in my admittedly old 1993 copy of the NEC.)

 

[Rocky_H]

NEC Table 210-21(b)(3) and Table 210-24 are pretty explicit as far as which receptacle ratings are to be used on various capacity circuits. (At least in my admittedly old 1993 copy of the NEC.)

Look at what those tables are describing. Those are specifically for branch circuits with multiple outlets on them. If it is a dedicated single-outlet circuit, those don't apply, and the only requirement is the circuit breaker not being above the outlet rating.

 

[wws]

Look at what those tables are describing. Those are specifically for branch circuits with multiple outlets on them. If it is a dedicated single-outlet circuit, those don't apply, and the only requirement is the circuit breaker not being above the outlet rating.

Good point!

 

[Paulteamblue]

I have a 32 amp Nema 14-30 dryer outlet in my garage. I also didn't want to plug and unplug my car and dryer all the time, so I bought this splitter on Amazon for $69. Parkworld 88603 NEMA 14-30 Splitter. It works like a champ.