Electrician question 120v/240v dual purpose cord.

I'm purchasing a unit the operates on 120v OR 240V with the flip of a switch. The manufacture tells you to cut the cord to make the change from 120v to 240v. With that said, I'd like the flexability to use this unit on either 120v or 240v whenever I please. I'd like to use my existing 240v receptable that my dryer uses or any other 120v receptacle of my choosing. In the video below, a guy makes a cord that would serve that purpose. 120v to 240v plug in Thoughts on this cord? I'm not an electrician. I understand the reason why the company tells you to cut the cord.
 
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I have seen this before. Someone, quite likely you, will inevitably come along and plug a 120 volt appliance into that 240 volt socket, and kaboom. It's only a couple of minutes to swap on a different plug if you wanted to change back.
 
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Won't work you'll have to decide if you want 120 or 240v.. A 120v cord will have a hot,neutral and ground.. The 240v cord in that setup is 2 hots and a ground. Play it safe if it came wired for 120v leave it. Don't get yourself killed.
 

dja4260

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Originally Posted by mk378
I have seen this before. Someone, quite likely you, will inevitably come along and plug a 120 volt appliance into that 240 volt socket, and kaboom. It's only a couple of minutes to swap on a different plug if you wanted to change back.
I expected a response such as this. You'd be correct that it would only take minutes to change out the end of the cord. I need to put the 240v on a GFI as well since I'll be playing with liquid.
 
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What is this unit? There are usually benefits to using 240V full time. But don't get caught up in the instant switching game from 120 to 240.
 
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You need a four wire feed. To get 120 the neutral carries current. I would think it requires a small panel then supply a 240 and 120 outlet separately from that panel. Check with a licensed electrician.
 

dja4260

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It's a homebrewing electric kettle. There is a switch on the unit, behind a cover that you switch for 120v / 240v. I have a 240v plug in my basement and workshop, and 120v on my patio and kitchen. I'd enjoy the flexability to brew where I choose based on weather, plans for the day, etc. 240v speeds up the brewing process significantly.
 
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Once you have tried both you'll never want to use it on 120 again. It is possible to make up 240 volt extension cords.
 
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The adaptor cable he shows will work just fine, it is identical to the adaptor that I received from the factory with my stick welder. The only difference is that my welder automatically senses the voltage and changes over but you have to remember to flip the switch, thats the very important part and only danger I see.
 
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Originally Posted by Farnsworth
You need a four wire feed. To get 120 the neutral carries current. I would think it requires a small panel then supply a 240 and 120 outlet separately from that panel. Check with a licensed electrician.
The 4 wire outlet (usually twist lock) will have 2 hot leads, a neutral, and a ground. Either hot lead to the neutral will give 120 VAC, the two hot leads would be 240 VAC. It would be possible to wire different receptacles, in different locations, for either 120 VAC (one of the hot leads won't be installed), or 240 VAC (won't need the neutral), but they would use the same plug. The 240 would be on a 2 pole breaker, the 120 would be on a 1 pole, and the plug/cord cap and receptacles are actually marked 120V/240V-that's what many generators use. I wouldn't bet on it passing code, but the only thing that would happen if you messed up would be a burned out brewer.
 
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I'm just a little confused why you would do this. The outlets are different depending if they're 120 or 240. There's a reason for standards. Plus a dryer is typically a 30 amp outlet and that's different than a 20 amp 240v oultet.
 

JHZR2

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You could take a 240 terminal, which is setup with two hots, a neutral and ground, and connect to it a multi-wire branch circuit. Thus you could have a 240V outlet, and on the other end of a conductor, TWO 120V circuits that share a neutral. That would be foolproof as long as the 240V end uses their NEMA receptacle, and the two 120V receptacles use the correct NEMA variant there. So you cant plug one into the other. But the design and female male polarity would need to be correct and foolproof. That said, that's related to the circuit design. Not the load. I wouldnt want something that could change at a flip of a switch, without something that forces an exclusive alignment if using 210 or 240. Not sure how to do that - its why the NEMA setups are what they are.
 
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Originally Posted by dja4260
It's a homebrewing electric kettle. There is a switch on the unit, behind a cover that you switch for 120v / 240v. I have a 240v plug in my basement and workshop, and 120v on my patio and kitchen. I'd enjoy the flexability to brew where I choose based on weather, plans for the day, etc. 240v speeds up the brewing process significantly.
So let me ask you this: the "home brewing" means for home use, not a home made kettle, right? In a nutshell the heating element is wired to either 120V or 240V with no electronics that can only work on 1 voltage / have to step down? You want to make sure you don't accidentally kill yourself if one of the "neutral" originally designed is touching the exterior then, I assume? How many amps are you using? If I were you I'd keep the cord as is (120V) and use an "adapter" to work around voltage difference, or if you want it really safe, use the Europe / British / Asia style 220-240V plug / socket so you don't accidentally plug something 120V into 240V and fry it.
 
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Originally Posted by bullwinkle
Originally Posted by Farnsworth
You need a four wire feed. To get 120 the neutral carries current. I would think it requires a small panel then supply a 240 and 120 outlet separately from that panel. Check with a licensed electrician.
The 4 wire outlet (usually twist lock) will have 2 hot leads, a neutral, and a ground. Either hot lead to the neutral will give 120 VAC, the two hot leads would be 240 VAC. It would be possible to wire different receptacles, in different locations, for either 120 VAC (one of the hot leads won't be installed), or 240 VAC (won't need the neutral), but they would use the same plug. The 240 would be on a 2 pole breaker, the 120 would be on a 1 pole, and the plug/cord cap and receptacles are actually marked 120V/240V-that's what many generators use. I wouldn't bet on it passing code, but the only thing that would happen if you messed up would be a burned out brewer.
Yes, but I was getting at if he has a three wire dryer outlet the ground wire and one hot will be carrying current on 120. Since ground wires are attached to any metal box or panel, it could be very dangerous. Neutrals are insulated all along until it gets to the service panel. Dryer circuits with three wires were not up to code like 30 years ago. It is very common for various electric devices to have a switch for voltages but from what i know it also includes a wiring diagram to rewire it. The owners manual would have the wiring diagrams and everything explained for that particular machine. I would never vary from that.
 

dja4260

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Originally Posted by PandaBear
Originally Posted by dja4260
It's a homebrewing electric kettle. There is a switch on the unit, behind a cover that you switch for 120v / 240v. I have a 240v plug in my basement and workshop, and 120v on my patio and kitchen. I'd enjoy the flexability to brew where I choose based on weather, plans for the day, etc. 240v speeds up the brewing process significantly.
So let me ask you this: the "home brewing" means for home use, not a home made kettle, right? In a nutshell the heating element is wired to either 120V or 240V with no electronics that can only work on 1 voltage / have to step down? You want to make sure you don't accidentally kill yourself if one of the "neutral" originally designed is touching the exterior then, I assume? How many amps are you using? If I were you I'd keep the cord as is (120V) and use an "adapter" to work around voltage difference, or if you want it really safe, use the Europe / British / Asia style 220-240V plug / socket so you don't accidentally plug something 120V into 240V and fry it.
It is a plug and play system, electronically controlled. Electric Kettle It is designed to NOT pull more than 15 amps with 120v, and less with 240v.
 
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In the video the guy says the company wants you to change the cord, and this is his idea to do it differently. Not recommended by the company. he says If everything is at 240v, like an electric baseboard heater has, it's ok not to have a neutral. But if the brewer has some 120v requirements like maybe the display, using the ground wire as a neutral like he did is a bad idea. You want to read the manual and only do exactly what they say and look at the wiring diagram, if you want to be safe. Which is the only reason I take time to post this.
 
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