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Is there an exterior wall pass-through device for a 240V outlet?

Is there an exterior wall pass-through device for a 240V outlet?


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Old 02-29-24, 07:10 AM
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Is there an exterior wall pass-through device for a 240V outlet?

I need 240V at the front of the house so I can charge an EV in the driveway. At this time I don't want to hard wire anything as the panel is all the way on the other side of the house and there are no empty spaces left in it anyway. Plus I'd have to tear open walls just run the wiring.

Since I would only charge once or twice a month, I could plug into the dryer outlet in the laundry room and use a 35' 240V extension cord down a hall, up the stairs to the kitchen bay window. Then plug the cord into a pass-through device mounted on the bottom of the bay window that would receive the car charging cable on the exterior.

My alternative is to just crack open a window in the bay window and position the cord through it and plug the car charging cable into it that way. But then I'd have to leave the window open overnight so bugs may crawl in.

Is there such a pass-through device? One that would receive the 240V extension cord on the interior, and I could plug the car charging cable into the exterior?
 
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Old 02-29-24, 12:35 PM
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Wire up a power inlet on the inside of the wall connected to a power outlet on the outside of the wall.
 
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Old 02-29-24, 01:38 PM
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If I could run a wire to the inside of that wall, then it would be no problem to put an outlet on the outside of it. But as I said, that's not feasible.
 
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Old 02-29-24, 02:18 PM
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I'm saying put a power inlet on inside of bay window wall and a power outlet on the outside of bay window. Plug in cord from dryer outlet to power inlet as you said.
 
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Old 02-29-24, 03:00 PM
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Something like this?


I can plug the extension cord from the dryer outlet into the interior part of it, and then plug the EV charger cable into the exterior part of it?
 
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Old 02-29-24, 04:12 PM
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I maybe wrong but I believe that is an inlet only and there is no exterior outlet side. I'm not sure a single device exists to do what you ask. I believe you need to wire a separate outlet device to the the inlet.
 
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Old 02-29-24, 05:30 PM
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A dryer outlet is only a 30 amp circuit. I assume you want to use a level 2 charger which typically needs a 120/240 volt 50 amp outlet. You will want to use an RV 50 amp extension cord which will run about $200 for a 50' cord.

Assuming that you will run the cord through the house you could just install a 50 amp outlet next to the electrical panel. Of course, you will need to put this outlet on a GFCI breaker.
 
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Old 02-29-24, 05:33 PM
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If the bay window is double hung and not casement, you could just make a piece of wood to fit under the window. Cut a slot in it to allow the extension cable to fit into the slot. Slip the cord into the slot, position it under the window and close the window on the wood block.
A real rube goldberg, and probably violates code in multiple ways, but would do as a temporary thing. Your insurance company would hate it, so better hope nothing goes wrong.
 
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Old 02-29-24, 05:58 PM
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My dryer outlet is on a 40A breaker.



The 240V EV chargers I see draw 32 amps max.

 
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Old 02-29-24, 06:34 PM
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That is a 10-30R (30A) outlet and is what's known as ungrounded. The "L" slot is neutral. That is not an appropriate outlet to use for the ev charger. Also it's a code violation to be on a 40A breaker.
 
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Old 02-29-24, 06:37 PM
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House built in 1965. Maybe it was allowed then?
 
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Old 02-29-24, 06:41 PM
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I've never known a 30A rated receptacle to be protected by a 40A breaker to be code compliant.
Better check the wire size.
 
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Old 02-29-24, 06:45 PM
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Inspected and signed off in 1967

 
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Old 02-29-24, 06:49 PM
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Sorry, that doesn't mean it's right or safe. I've seen inspectors miss things and just do poor inspections.
I highly suggest not using that circuit for the ev charger. You really need to verify the conductor type and size of that circuit.
 
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Old 02-29-24, 07:02 PM
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Inspected and signed off in 1967
Are you the original owner? If not then many things could have changed in 50+ years

That dryer outlet is only rated for 30 amps max. It is also an ungrounded outlet and not suitable for an EV charger.
 
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Old 02-29-24, 07:10 PM
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Can you tell what gauge it is?


 
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Old 02-29-24, 07:17 PM
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You said it was not feasible to string a cable from the breaker box, up inside the wall, and over to the place where the car is parked.

Go back to reply #2.

You need the following parts:

1. A receptacle on the outside wall to plug your charger cord into. This receptacle might look similar to the one in reply #9 or the one in reply #16 but you will need to select the exact ampere rating, more on that later.

2. A receptacle in the same place on the inside wall to connect to a power source such as from your dryer receptacle or your (electric) stove receptacle using an extension cord. This has to be of the same amperage as #1. This must be a male receptacle aka inlet, namely with protruding prongs instead of slots in the face. It is perfectly safe because the prongs are live only when you put the live extension cord (from the stove receptacle) female end over them. Nothing outside is capable of injecting power to make the prongs live while still exposed.

3. A short cable to connect #1 and #2. This whole assembly is mounted in one place on the exterior wall where you drill a hole to stick the cable through.

4. You will need some accessories such as a weatherproof box on the outside and a protective box on the inside to hold the receptacles, connect up the wires inside, and prevent touching live wires when you are finished assembling all this..

5. Added later, just read another post someone saying that their car charger does not work on an ungrounded circuit. So the parts you buy must be for grounded circuits, with 4 prongs -- two for 240 volts, one for neutral, and one for ground. I take it that your charger's cord you plug into the wall outside has 4 prongs.

(The same arrangement would also be used for 120 volts except that the receptacles have a different prong hole pattern.)

About amperage, you start with the amperage of the stove or dryer receptacle that will feed all this. Most likely 30 amps or 40 amps. If you need or want 32 amps then the breaker for the supply circuit (e.g. existing stove receptacle) and extension cord and receptacles need to be 40 amps. For the length of time the car is charging you are allowed to draw no more than 80% of the circuit (breaker rating and receptacle rating). If you are using a 30 amp dryer receptacle to power all this then you must dial back the car charger to draw no more than 24 amps.
 

Last edited by AllanJ; 02-29-24 at 07:57 PM.
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Old 03-01-24, 06:33 PM
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Can you tell what gauge it is?
That looks bigger than #10 which is typically found on 30 amp dryer circuits. But that receptacle is only rated for 30 amps.

Also, that is a 240 volt, 3 wire circuit. EV chargers need 120/240 volt 4 wire circuits.
 
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Old 03-01-24, 06:57 PM
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Old 03-02-24, 03:23 AM
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Will it work? It might. But if you try to power a device that draws more power than the circuit is designed to supply, the breaker is going to trip.

If the breaker doesn't trip, you will be drawing more power than the wiring is rated to handle, possibly causing a fire. The insurance company will investigate, find non-compliant devices and deny the claim.

I seriously doubt it carries the listing mark of a Nationaly Recognized Testing Laboratory. If it does, I would verify the listing since counterfeit listing marks have been found on the big A before.

When dealing with safety (and electrical "work arounds" are very much safety related), do it right.
 
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Old 03-02-24, 06:29 AM
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That adapter does not provide the 4 wire connection that the EV charger will require. Also, it will still overload the 30 amp receptacle.
 
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Old 03-02-24, 06:35 AM
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1) What is the 4th wire that the EV charger needs but the dryer doesn't?

2) I understand the charger draws a maximum of 32 amps. A 30 amp receptacle isn't designed to withstand a slight overage? A margin or cushion of error so to speak? And I don't think it would be at 32A continuously or even for very long unless the battery was totally empty.
 
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Old 03-02-24, 06:35 AM
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The 4th prong is for grounding. Some chargers do not need the nuetral but do need the ground. Some chargers need both neutral and ground.

Car charging is more likely than not to run for more than 3 hours.
 

Last edited by AllanJ; 03-02-24 at 07:23 AM.
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Old 03-02-24, 06:37 AM
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All EV chargers do not require 120V/240V 4 wire circuits. Some only use 240V. Some manufacturers give option to use either a 4 prong or 3 prong plug to fit outlet you have but does not use the neutral.
 

Last edited by pattenp; 03-02-24 at 06:47 AM.
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Old 03-02-24, 11:56 AM
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Every level 2 changer I have installed required a 120/240 volt 50 amp receptacle NEMA 14-50. That is 4 wires. (hot, hot, neutral, ground)
 
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Old 03-02-24, 12:43 PM
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Tolyn Ironhand What about This adapter?

 
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Old 03-02-24, 12:47 PM
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I've seen EV 240V chargers that come with a 14-50 plug but actually don't need the neutral. They are wired with the 14-50 as a matter of common availability, not because a neutral is needed.
Do some research and you'll see.
 
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Old 03-02-24, 03:36 PM
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That adapter still does not address the issue that the receptacle is only rated for 30 amps.

I've seen EV 240V chargers that come with a 14-50 plug but actually don't need the neutral. They are wired with the 14-50 as a matter of common availability
So, NEMA 6-50 devices are not commonly available? If it comes with a 14-50 plug I will always assume it requires a neutral. Plus, we do not know what charger will be used. The one he gets may require a neutral.

Should I also mention that EV chargers are required to be GFCI protected.
 
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Old 03-02-24, 03:51 PM
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6-50 devices are commonly available as a purchasable item, but are not as widely installed in homes as the 14-50. I should have said more commonly installed vs. available.
 
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Old 03-02-24, 05:22 PM
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That looks bigger than #10
The wire looks to be aluminum or more of a possibly is copper clad aluminum so that is probably why it looks bigger than #10

 
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Old 03-03-24, 07:18 AM
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If you don't know what you are doing, and you are getting conflicting advice on a forum, somewhat due to lack of complete information, please hire an electrician and do it right. If you are going to keep an electric car, consider properly installing a correctly wired ESVE. There are often credits available and, in my opinion, an ESVE should just be considered as one of the required expenses of buying the car. You will never regret the convenience vs. an outlet, and it will add future value to your house.
 
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