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So before I begin let me say I am a complete idiot when it comes to anything electrical besides the very basics. So I am working on a project where I am powering something that needs 240 volts AC. So what I have done is taken two male outlets and wired them with 10 gauge wire to a common female plug. I have attached a picture below. enter image description here

enter image description here

Now this is where my lack of electrical knowledge is hurting me here. When I plug these into different outlets it only gives 120 volts. I have done some research and found out they need to be on different circuts so I tried that as well. Only gave me 120 volts. I also heard something about being "180 degrees out of phase". Now please don't bully me too much but I have absolutely no idea what that means. If anybody could help me out that would be great. Also if you need more pictures I would be glad to supply them.

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    \$\begingroup\$ How have you wired that Y-cord? If the "hot" wires from the two male plugs are connected together, you can only get 120 volts. If you plug them into outlets that are on opposite "phases", you will blow circuit breakers. Attempting to get 240 V like that is extremely hazardous if you don't know what you are doing (and not advised if you do know what you are doing!) You can get 240 V from a stove or clothes dryer outlet. (but you should still know what you are doing - call an electrician if you don't know). \$\endgroup\$
    – Peter Bennett
    Oct 31, 2016 at 3:06
  • \$\begingroup\$ @PeterBennett If the hot wires are not supposed to be touching how would it be wired. The way it is currently wired the 2 neutrals are touching, the 2 hots are touching, and the 2 grounds are touching. \$\endgroup\$
    – xFlarp
    Oct 31, 2016 at 3:10
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    \$\begingroup\$ DO NOT attempt to use your Y-cord to get 240 V - you'll blow breakers and may cause fires. As you admit that you are a "complete idiot" re electricity, I strongly suggest that you consult an electrician if you need a 240 volt outlet. \$\endgroup\$
    – Peter Bennett
    Oct 31, 2016 at 3:16
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    \$\begingroup\$ I'm voting to close this question as off-topic because this question is not only based on a faulty premise, but it is EXTRAORDINARILY DANGEROUS and should not be published online even as a way to NOT do something. \$\endgroup\$
    – Richard Crowley
    Oct 31, 2016 at 3:31
  • \$\begingroup\$ Yeah, that Y cable should be destroyed. But I did see a video on youtube once where a guy (not an idiot) did something similar to get 240 in Canada. He asserted that in Canada, most outlets have two 120V plugs which are out of phase from each other. Thus giving 240. But I wouldn't expect it work in the US. \$\endgroup\$
    – user57037
    Oct 31, 2016 at 3:48

3 Answers 3

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If you try to understand how the 120/240Vac 60Hz is distributed, you would need a much longer Y adapter to combine opposite phases to get 240V. Each phase labelled as Line 1 and Line 2 (Black and Red) in North American standards is distributed around the house to balance the load, and both are wired to the oven and electric dryer. IN North America a differnt larger plug and outpet is used for 240Vac and NEVER the same as used for 120Vac. enter image description here - > But they are never both wired to a dual low current outlet. (10~20A)

The usual method is a 240 V cable direct from the breaker panel as adjacent dual outlets always have the same phase wired to them. Water heaters rated for 240 do not need neutral so a 2 wire +gnd is all that is needed while a stove/oven requires both L1,L2 and N for 120Vac lights, clock and accessory outlets, so a 3 wire power cable + gnd is used.

Normally household wire is Black (Line=hot) and WHite (neutral) and Black may be used for either Line 1 or Line 2.

Thus your example Y cable is a mistake in understanding.

enter image description here enter image description here

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  • \$\begingroup\$ the problem with a "properly" wired 2x120v-to-240v cable is that if you connect the 240v load and only plug in one 120v plug, the hot prong of the other plug will have 120 volts on it, conducted through the load device. Ready to electrocute a careless user! Also, this will not work at all on GFCI outlets or circuits. \$\endgroup\$
    – DoxyLover
    Oct 31, 2016 at 4:21
  • \$\begingroup\$ I can't imagine anyone trying to do this except candidates for the Darwinian Awards. \$\endgroup\$
    – Tony Stewart EE75
    Oct 31, 2016 at 4:25
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This "solution" is so wrong on so many levels it is hard to know where to start. The solution shown is practically DESIGNED to both electrocute you AND burn down your house. Absolutely NOT RECOMMENDED in any way, shape or form.

There are two acceptable and safe ways of getting 240V for your project:

  1. Wire a proper 240V circuit from the power distribution breaker box.
  2. Use a 120V to 240V step-up transformer. (Assuming sufficient power for your undisclosed requirements.)
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Tony's answer gave you the theory without explicitly telling how to "correctly" wire your cable. I'm not going to either. I want to make sure you understand the hazard. If you connect your 240 volt load, turn it on but only plug in one of the 120v plugs and then grab the prongs of the other plug, you will get a heck of a shock and could be electrocuted!

The 120 voltage enters through the hot prong of the plugged-in plug, conducts through the 240 volt device and ends up on the other plug's hot prong where it's just too easy to touch.

Don't do it!

BTW, it also won't work at all if your 120v outlets are GFCI or on GFCI breakers.

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