240v through the 5-15 plug?

[n2mb_racing]

Agreed, 240 in a 120V outlet in the wall is a bad idea.
A NEMA 6-15 to 5-15 adapter is a much less bad idea. Especially if it is well labeled and kept with the car...

 

[SomeJoe7777]

I have not once intended to suggest installing a 5-15 outlet into your house with 240V.

That is indeed exactly what you suggested, twice:

the only concerns you have using a 5-15 connector with 240V are the following:

• Can the mobile connector accept two hot wires (120V in dual phases) on a 5-15 connector (i.e. is it wired to accept this internally)
  
• Amperage pulled through the line does not exceed original specs of 5-15 connector (i.e. 15 amps)

... there is no reason to buy another adapter if you're being mindful of your wiring.

... if there happens to be 240V at the hot and neutral, it should just work as if you had a Tesla 6-15 connector on it. The real risk is you might accidentally plug in a 120V only plug into your now 240V outlet without thinking. THAT is the real danger. There is no electrical or physical reason that this setup is dangerous; it's just the idiot factor you have to worry about.

If you're being careful, physically, there is no danger to using a 5-15 for 240V. Just be sure of what you're plugging in.

 

[Aphinity]

That is indeed exactly what you suggested, twice:

Actually, in each case, my intention was discussing the 5-15 on an extension cord. I can see now why that is not how it was interpreted though. I wish I could edit those to add that, but I can't, sadly.

Thanks for pointing that out, @SomeJoe7777. I can definitely see how that could have been misinterpreted.

 

[SomeJoe7777]

Actually, in each case, my intention was discussing the 5-15 on an extension cord.

How would you even do that? You're not seriously contemplating creating a Y-shaped extension cord with two 5-15P plugs that are then wired such that their respective hots go to each side of a 5-15R receptacle are you?

This is called a "suicide cord" for a very good reason. If the outlets you happen to plug it into aren't on separate circuits it will immediately create a phase-to-phase short. That is virtually guaranteed to damage equipment or start a fire.

And in any case, there is already a company (who actually knows what they're doing) who has created a safe way to do this: Quick 220 Systems: Model A220-15D For Equipment with US/Canadian Plugs

 

[Aphinity]

How would you even do that? You're not seriously contemplating creating a Y-shaped extension cord with two 5-15P plugs that are then wired such that their respective hots go to each side of a 5-15R receptacle are you?

This is called a "suicide cord" for a very good reason. If the outlets you happen to plug it into aren't on separate circuits it will immediately create a phase-to-phase short. That is virtually guaranteed to damage equipment or start a fire.

And in any case, there is already a company (who actually knows what they're doing) who has created a safe way to do this: 110-120 and 220-240 Voltage Converters & Accessories

Actually yeah, that's what I'm describing, somewhat, although I don't understand why it's quite as you describe.

I wanted to use the two hots on opposing split-phase circuits plugged in with dual 5-15 male connectors. Each respective hot from each 5-15 male would be wired into one hot each of a 6-15 female connector. This setup ran a 240V kettle at my work for years (I didn't wire it, I was only told about the solution). The solution you linked seems to do exactly that, only with a wiring safety check included. Definitely seems prudent. I planned to check the potential between hots using a volt meter before plugging in to verify the opposing split phases to make a single phase 240V.

In your example, if the cord was plugged into the same split-phase for both hots, wouldn't that just be a potential of 0 and provide no current? I can see the danger if you have the device plugged in BEFORE plugging in both ends of the Y, as one may be electrified, and those prongs are exposed.

 

[n2mb_racing]

How would you even do that? You're not seriously contemplating creating a Y-shaped extension cord with two 5-15P plugs that are then wired such that their respective hots go to each side of a 5-15R receptacle are you?

This is called a "suicide cord" for a very good reason. If the outlets you happen to plug it into aren't on separate circuits it will immediately create a phase-to-phase short. That is virtually guaranteed to damage equipment or start a fire.

Ok, I'm curious. Why would it be a problem if you short together two hots that are on the same phase? They would be at the same or nearly at the same potential, so the output at the 240V outlet would be net ~0 V.

The Y cord would be two 5-15P plugs and one 6-15R. The hot from each plug goes to the hots of the 6-15R. The neutrals are left out and the ground is connected through.

I think the suicide cord you are referring to is a 5-15P to 5-15P cord, which is a bad idea because the plugs are energized as soon as you plug in one side. In this Y cord, the 5-15P plugs would not be energized as long as the 6-15R was connected LAST, after the 5-15P plugs are both in.

 

[SomeJoe7777]

Ok, I'm curious. Why would it be a problem if you short together two hots that are on the same phase? They would be at the same or nearly at the same potential, so the output at the 240V outlet would be net ~0 V.

The Y cord would be two 5-15P plugs and one 6-15R. The hot from each plug goes to the hots of the 6-15R. The neutrals are left out and the ground is connected through.

I think the suicide cord you are referring to is a 5-15P to 5-15P cord, which is a bad idea because the plugs are energized as soon as you plug in one side. In this Y cord, the 5-15P plugs would not be energized as long as the 6-15R was connected LAST, after the 5-15P plugs are both in.

You are correct, it would not create a phase-to-phase short. In my head I was thinking something different. The neutrals are not connected, and the hots are on separate pins, so no circuit is formed until a device is plugged into the 5-15R (or 6-15R).

That actually makes me feel better.

However, there are other issues.

1) We still have the risk that someone could plug a 120V device into the 5-15R at the end of the extension cord.
2) This setup will not work with GFCI outlets, as they will trip when they see no current on the neutral. Furthermore, most modern homes now have the GFCI protection at the circuit breaker instead of the outlet, so there are fewer and fewer non-GFCI outlets that you can use this for. (The Quick 220 has the same problem).
3) As n2mb_racing said, if the 240V device is plugged into the 5-15R receptacle before both 5-15P plugs are plugged into outlets, then the exposed pins on the unconnected 5-15P will be energized. Obviously this is a hazard.
4) You don't have any verification that the outlets are wired correctly. It is quite common for a 5-15R receptacle to be wired backwards, i.e. neutral and hot reversed. If one of the outlets is like this, you won't get the 240V at the 5-15R end of the extension cord.
5) If one of the 5-15 plugs is live, and the other one is dead because the breaker is turned off, the dead plug will be fed with 120V from the other plug through the device. If the breaker was turned off because someone was working on that circuit, they are now exposed to live electricity inadvertently. Similarly, if there are devices on that circuit, they will now be in series with the load on the 5-15R end of the extension cord, resulting in partial voltage to all devices, which could damage them.

In short, I still think it's a bad idea.

 

[Aphinity]

@SomeJoe7777 Now that's some good feedback! I had not considered the idea of feeding back into a turned-off breaker. Definitely a concern. If one of two circuits were to blow, you would definitely want to disconnect the live side immediately.

Maybe one day I will live in a place where I can wire in a proper outlet. For now, I'm not charging at home at all. The more we discuss this, the more I realize I should just not bother, even though I now know how.

 

[n2mb_racing]

You are correct, it would not create a phase-to-phase short. In my head I was thinking something different. The neutrals are not connected, and the hots are on separate pins, so no circuit is formed until a device is plugged into the 5-15R (or 6-15R).

That actually makes me feel better.

However, there are other issues.

1) We still have the risk that someone could plug a 120V device into the 5-15R at the end of the extension cord.
2) This setup will not work with GFCI outlets, as they will trip when they see no current on the neutral. Furthermore, most modern homes now have the GFCI protection at the circuit breaker instead of the outlet, so there are fewer and fewer non-GFCI outlets that you can use this for. (The Quick 220 has the same problem).
3) As n2mb_racing said, if the 240V device is plugged into the 5-15R receptacle before both 5-15P plugs are plugged into outlets, then the exposed pins on the unconnected 5-15P will be energized. Obviously this is a hazard.
4) You don't have any verification that the outlets are wired correctly. It is quite common for a 5-15R receptacle to be wired backwards, i.e. neutral and hot reversed. If one of the outlets is like this, you won't get the 240V at the 5-15R end of the extension cord.
5) If one of the 5-15 plugs is live, and the other one is dead because the breaker is turned off, the dead plug will be fed with 120V from the other plug through the device. If the breaker was turned off because someone was working on that circuit, they are now exposed to live electricity inadvertently. Similarly, if there are devices on that circuit, they will now be in series with the load on the 5-15R end of the extension cord, resulting in partial voltage to all devices, which could damage them.

In short, I still think it's a bad idea.

Good points. You can solve #1 by using a 6-15R or 6-20R outlet so that someone can't get that wrong.

Anyway, I don't plan on making one soon, since I'm not traveling anywhere with covid. And using a dryer outlet with a 6-50 adapter and 6-50 extension (with amps dialed down to 24) seems like a better option if fast charging is needed.

Of course, if you are staying anywhere for a more than a few days, you can get a full charge with 120V, so why bother with any of this?

 

[SomeJoe7777]

And using a dryer outlet with a 6-50 adapter and 6-50 extension (with amps dialed down to 24) seems like a better option if fast charging is needed.

That's what I do for out-of-the-way locations that have no other charging options. I have 10-30 -> 14-50 and 14-30 -> 14-50 adapters for charging from dryer outlets. Just make sure to turn the amps down to 24A in the car.

 

[Aphinity]

That's what I do for out-of-the-way locations that have no other charging options. I have 10-30 -> 14-50 and 14-30 -> 14-50 adapters for charging from dryer outlets. Just make sure to turn the amps down to 24A in the car.

You may be interested to know, others have verified that cutting the neutral pin off of your 14-30 or 14-50 connector will make it work on both outlets, obviously keeping in mind to remember to set the amperage lower where necessary.

 

[eladts]

Agreed, 240 in a 120V outlet in the wall is a bad idea.
A NEMA 6-15 to 5-15 adapter is a much less bad idea. Especially if it is well labeled and kept with the car...

Since the native Tesla NEMA 6-15 and 6-20 adapters are available for a very reasonable price, I see no reason to use the less bad idea.

 

[n2mb_racing]

Since the native Tesla NEMA 6-15 and 6-20 adapters are available for a very reasonable price, I see no reason to use the less bad idea.

Agreed. I said that earlier. That's what I'm using now. 6-20 outlet and 6-20 UMC plug for one car and 14-50 for the other.

 

[beachfitrob]

Here's a safe scenario: I use an L6-30P to 5-15R socket cord. It's a 25' or so extension caple that I used to just plug my L6-30P equipped Nissan Gen 1 EVSE into. It was modified to do 240V at 20A, hence L6-30 which is good to 24A. I replaced the L6-30R with the 5-15R.

Never had an issue.

The other use for it is when I would take my EVSE with me for emergency campground use on my Bolt and I would leave the adapter plugged into the Chevy EVSE since my leaf could only draw 16A anyway, so 12 was reasonably close to max.

The Chevy EVSE is also happy at 240V 12A.

I already had the cord so at that point, receptacles are cheap.