Do It Yourself: 240v from two 120v sources

[smkettner]

Unless similar is available UL listed and NEC compliant I am going to stick with 120v or a proper 240v connection.
I would not use it if it was free.

 

[TomT]

I'm an electrical engineer so I feel pretty comfortable with the design and safety of it... There's nothing necessarily magical about UL or NEC... Besides, both the Sonalert and light are UL approved. :lol:

Unless similar is available UL listed and NEC compliant I am going to stick with 120v or a proper 240v connection.
I would not use it if it was free.

 

[davewill]

Unless similar is available UL listed and NEC compliant I am going to stick with 120v or a proper 240v connection.
I would not use it if it was free.

Then why are you posting in a DIY thread where, I can pretty much guarantee, nothing will be UL listed? Besides, unless you have the also not UL listed EVSE upgrade, it wouldn't be very helpful, anyway.

 

[Volusiano]

Unless similar is available UL listed and NEC compliant I am going to stick with 120v or a proper 240v connection.
I would not use it if it was free.

You'd probably be better off buying the Quick220 for $185, then.

Even the Quick220 is not UL listed. They say it "meets" UL standard 1012 (whatever it means), but it's tested and listed by Intertek, a lab approved by OSHA to test products for workplace safety.

 

[z0ner]

Very good point davewill. There is a certain inference in a DIY thread that it's a do-it-yourself If you're not comfortable with it, forward this info to someone more knowledgeable that can do this for you, or probably best to just move onto the next thread.

The risks are very well known, and have been explicitly spelled out several times.

 

[Volusiano]

I wonder if somebody would be willing to estimate the parts cost to build the whole thing (let's say with 8' long 120V cords and the L6-20 receptacle, of course). This will help determine how much motivation people can get to take on this project.

 

[JimSouCal]

I wonder if somebody would be willing to estimate the parts cost to build the whole thing (let's say with 8' long 120V cords and the L6-20 receptacle, of course). This will help determine how much motivation people can get to take on this project.

$75 to 150. Meeting your level of motivation with the accuracy of my estimate. In a few weeks, will do better.

 

[TonyWilliams]

In he box containing the relays and other electronics, perhaps mounting L6-20s for the 120 volt input. That way, a standard extension cord (12/3) with L6-20s could also be used as an extension cord for 240. Lots of combinations that way.

 

[Ingineer]

OK, my trip to the junk boxes resulted in some components that I used to build a slightly different version. The relay logic and wiring is the same as the schematic (I didn't use the 120/240 switch). However, I went with a different type of noise maker and light based on what I found.

I have an old 240VAC Sonalert that is a momentary type (it sounds for 5 second than goes off when power is applied) and I used that by wiring it directly across the 240 output through two 10 ohm 1 watt fusible resistors (one on each side of the Sonalert) for short protection.

Across the Sonalert I wired a 240 volt Neon cartridge indicator that I also had in parallel. Testing showed that the Sonalert wouldn't trigger on 120 but would on 240 so it was perfect for this. Likewise, the light is very dim on 120 but quite bright on 240.

Not as elegant but having all the parts available in the shop was a plus.

This seems fine. It does not matter if the buzzer/light work on 120v, as they will never see that unless you have the switch. If you plug the 2 plugs into the same circuit it will see 0v, and on opposing circuits it will see 240v. The only way it would ever have 120v is with the switch option which you are omitting.

Also, (for everyone else) *NEVER* connect anything before the relays, such as buzzers and lamps! They all must connect to the L6-20 side in order to be safe!

-Phil

 

[Ingineer]

Unless similar is available UL listed and NEC compliant I am going to stick with 120v or a proper 240v connection.
I would not use it if it was free.

If I were you, I'd avoid reading any topics that begin with "Do It Yourself". I like to request that you at least avoid the silly comments. It's very obvious to everyone that it's a DIY project. I have already stressed that nobody attempt this unless they are qualified to work on high-voltage electrical projects.

It's questionable whether any kind of device like this could meet NEC. Can it be safe? Definitely.

Keep in mind the NEC (National Electrical Code) is written by the NFPA (National Fire Protection Association), which is largely made up and financed by fire insurance companies. Their motivations can sometimes be, shall we say, "excessive" compared to reasonable engineering standards. Thusly, the code is extremely harsh on 240v in this country, which is why we have so much trouble charging our EV's. People have been using 240v all over the world for almost a century, and WE are being injured more often than they are!

I call this the "Danger: This sign has sharp edges" phenomenon. We are so concerned with liability that we try hard to protect people from everything, including their own stupidity. The big problem is this kind of thinking actually breeds stupidity! When I was a kid, the playground was a rough place. There were about a thousand ways to seriously hurt yourself. You quickly learned to hone that self-preservation instinct and not kill yourself in a freak monkey-bar accident. Has anyone seen a playground lately? They are all neoprene-coated, safety-padded, non-toxic, yellow stickered, no unattended childen allowed places! We are slowly removing the impetus for people to think for themselves and learn from their mistakes. If you don't make mistakes, you can't learn from them, it's that simple. We are closing parks because they have "dangerous" places, like cliffs without safety railings and on-duty safety officers. It's insanity! So excuse me if I react unkindly to FUD.

If you are bored, go on over to the Chevy Volt forum and start a big ruckus there, the L1 EVSE that they ship with the car is NOT UL listed if you can believe it! They use 16awg wire throughout, and the unit is not even sealed from water ingress. One good drop on the pavment and it will crack wide open also. I doubt it would even pass UL's tests.

-Phil

 

[mwalsh]

I call this the "Danger: This sign has sharp edges" phenomenon.

What he said!

I was going to post a picture of the "Caution: This sign has sharp edges" sign. But then happened upon a picture of a naked chick with a "Will work for sex" cardboard sign and got a bit distracted.

 

[Ingineer]

Can someone elaborate on why you'd want the 120v switch? I must be missing something. Seems to me if you want 120v, just don't use this device at all...

Well, I use it for testing. There are a lot of possible uses, one is that it can be used on only one outlet in 120v mode, so it allows the same unit to double as a 8 foot long 120v adapter in the event you can't find 2 non GFCI circuits.

Scenario: You get your "Easy240" out, search for plugs, but cannot locate 2 on opposing circuits, so you simply throw the switch to 120v and not have to deal with another trip to the trunk to retrieve the 120v adapter.

Another: You are plugged into 2 circuits in your kitchen, but your wife wants to make you some toast and cord #2 is sharing the outlet with the toaster. Rather than unplug your car completely, she can simply switch the toggle over and the car will continue charging on 120v while your toast is being made. Then when she is done, she can kick it back to 240v. The car will never stop charging, and you won't have to go reset anything.

-Phil

 

[Ingineer]

I call this the "Danger: This sign has sharp edges" phenomenon.

What he said!

I was going to post a picture of the "Caution: This sign has sharp edges" sign. But then happened upon a picture of a naked chick with a "Will work for sex" cardboard sign and got a bit distracted.

 

[GeekEV]

Can someone elaborate on why you'd want the 120v switch? I must be missing something. Seems to me if you want 120v, just don't use this device at all...

Another: You are plugged into 2 circuits in a kitchen room, but your wife wants to make you some toast and cord #2 is sharing the outlet with the toaster. Rather than unplug your car completely, she can simply switch the toggle over and the car will continue charging on 120v while your toast is being made. Then when she is done, she can kick it back to 240v. The car will never stop charging, and you won't have to go reset anything.

I hadn't thought of that scenario. Yeah, I could see that being useful to some people...

 

[TEG]

I call this the "Danger: This sign has sharp edges" phenomenon. We are so concerned with liability that we try hard to protect people from everything, including their own stupidity. The big problem is this kind of thinking actually breeds stupidity! When I was a kid, the playground was a rough place. There were about a thousand ways to seriously hurt yourself. You quickly learned to hone that self-preservation instinct and not kill yourself in a freak monkey-bar accident. Has anyone seen a playground lately? They are all neoprene-coated, safety-padded, non-toxic, yellow stickered, no unattended childen allowed places! We are slowly removing the impetus for people to think for themselves and learn from their mistakes. If you don't make mistakes, you can't learn from them, it's that simple. We are closing parks because they have "dangerous" places, like cliffs without safety railings and on-duty safety officers. It's insanity! So excuse me if I react unkindly to FUD.

Book: 50 Dangerous Things You Should Let Your Children Do

 

[GeekEV]

It does not matter if the buzzer/light work on 120v, as they will never see that unless you have the switch. If you plug the 2 plugs into the same circuit it will see 0v, and on opposing circuits it will see 240v. The only way it would ever have 120v is with the switch option which you are omitting.

Wouldn't it also see 120v if one of the sockets is wired wrong? You'd still flip both relays, but would be bridging a hot and neutral - so 120v... Right? <still learning>

 

[Ingineer]

It does not matter if the buzzer/light work on 120v, as they will never see that unless you have the switch. If you plug the 2 plugs into the same circuit it will see 0v, and on opposing circuits it will see 240v. The only way it would ever have 120v is with the switch option which you are omitting.

Wouldn't it also see 120v if one of the sockets is wired wrong? You'd still flip both relays, but would be bridging a hot and neutral - so 120v... Right? <still learning>

Correct! Although this is pretty rare.

-Phil

 

[davewill]

Not wanting to try and build the LED/buzzer circuit, I was thinking that I could cannibalize a simple 2 wire voltage tester for my "circuits OK" light. (Yeah, no buzzer.)

Although, with the relays in there, you could, I suppose, just plug in the EVSE and look for it's green light :shock: ...OK maybe not. As far as the Hot-Neutral problem, GeekEV, I already threw a regular 3-pin socket tester in my kit. Figured it was cheap insurance.

 

[johnr]

I'm trying to think of how useful such a device would be. In my garage I can use the dryer plug or have another 240V outlet installed. So this would be something to bring when going on a long trip. But in a location where there are two out of phase 120V outlets, there is likely to be a 240V outlet as well, right? For that matter, in most places where there is 120V, there's likely to be 240V. So, what would be the advantage? Maybe it's easier to ask to borrow a 120V outlet. But to have two long cords strewn across the place to get at two outlets might be too much of an imposition to one's guest. I'm just not sure...

 

[GeekEV]

As far as the Hot-Neutral problem, GeekEV, I already threw a regular 3-pin socket tester in my kit. Figured it was cheap insurance.

I picked up a $20 digital multimeter at Radio Shack for the same purpose. Not as simple to use though.

But in a location where there are two out of phase 120V outlets, there is likely to be a 240V outlet as well, right?

At someone's house (particularly if its a recent construction) - yes. In retail locations, not likely. Or, if they do, they're either in use or not in a location accessible to you. From what I'm given to understand, many outdoor 120v outlets tend to be on dedicated circuits. This is particularly true if you have a public charger location with outdated paddles (or something you can't use) - you could still use them by grabbing two 120v outlets if they offer them (many do). But I tend to agree, for me I don't see this being that useful, but the DIY version seems pretty cost effective so I may do it anyway.