Device for Connecting Two 110 VAC to Make One 220 VAC

I can assure you there is no such device available commercially. It is both dangerous and "illegal" (you don't go to jail, but your fire insurance company can refuse to replace your house if you do this).

I know this because I've done exactly what you want to do. I know a great deal about electricity and I had no problem; I meant to do this only for a few days till I had time to run a 220 circuit. However, Igor (names have been changed to protect the stupid), my assistant, walked in the lab and partially disconnected my rig-up. Being neat (possibly his only good quality), he hung the offending connector up on the side of my relay rack. A fair amount of expensive equipment and much of my remaining hair went up in smoke (who knew a 20A breaker could hold out that long?).

So, don't do it. It's dangerous, dumb, and potentially expensive.

Do you have the option (and knowledge) of putting in a 220 volt circuit?

Simple & safe way is to get a step-up transformer. Google for 110/220 TRANSFORMER, there are lots available. Not too costly, if your saw doesn't draw a lot of currrent.

I agree it can be dangerous. Avoid it.

But, answering your question, it would only work if you had in your installation two outlets comming from a 3 phase circuit, in two different phases, and was able to install an outlet that was powered from the 2 different phases (not the neutral).This way you'd end up with the suggested 220V circuit, more specifically, the tension between two different 127 VAC phases discounted the phase angles. This is what I have at home: a 3 phase 127 VAC circuit that in some outlets provide 220 V.

If you connect two outlets from the same powering circuit, you have two possibilities: 1. Nothing occur, and you end up with 110V and a neutral but powered by two outlets, or 2. You may connect the power and neutral of the two outlets to each other, short circuiting it. Guess by Murphy law what you'd do more easily...

If EL/ELCB/whatever breakers are installed, they will keep tripping.

Actually this is not an unusual question, I was called to a job cause the newly installed motor drive was tripping the saftey breakers in a steel rolling facility, returned the drive 2 times for checking, finally went down there and found they ran 2 power cords to the motor drive (required 240VAC)

Well, the close outlet was only a 3-PH-4 pin socket (L1, L2, L3 & E) so a 2nd line was run from another part of the factory to pull in the Neutral (instead of running the L1/2/3 from that lead) having 2 different current paths, the saftey switches would instantly trip every time.

As long as your saw does not require more than 7.5 Amps then you can use a transformer to boost the 120v you have to the 220v you need. (Most residential circuits are breakered for 15A which is what you will draw if your saw needs 7.5A)

If you do try this - please video it for us.

If you are in the US, your house is already wired for 240V. The expense of a transformer and all of the proper protection devices will be higher than the cost of just having a qualified electrician run a new 220V outlet in your garage or workshop. By the way, f your house was wired for an electric dryer, that will be a 240V outlet and many home shop owners just unplug the dryer and plug in the power tool!

Serves a dual purpose in making it so that you can't help out with the laundry at the same time...

The "two extension cord" version is dangerous and illegal as previously mentioned. In doing that (and ASSuming you can find two putlets of opposite polarity), the circuit breakers would not be mechanically linked and you could blow one circuit breaker but not the other, which sets up an extreme hazard. That is why it is illegal.

Dear Mr. JRaef

Dear Sir, Regards,

in post #7

<< If you are in the US, your house is already wired for 240V. .. >>

In a Question I ask for 110 & 220 V supplies in States as under & most of the replies confirmed in :

Domestic-Power-in-USA

<<

#1 Most USA residences have both 110V and 220V circuits. Standard wall outlets, however, are 110V. Kitchens often have 220V for the stove. Laundry rooms usually have 220V for clothes dryers. Garage areas often come equipped with 220V outlets for a welder or other use. People often have special circuits installed for various purposes by qualified electricians, unqualified electricians (bad idea) etc. >>

Is it possible to know which parts of NewYork & Harperwoods [Detriot] have both 110V and 220V supplies.

Some of my relatives have settled in States some time back & could not find 220V Wiring in their houses/ Flats/Apartments.

I informed them that in USA most of the houses have 220V supply also on the information of replies to my post above.

Thanks & regards.

Wow - Thank you all for your comments. You folks are very helpful.

The transformer sounds like a good fit, but the google search for "110/220 TRANSFORMER" came back with lots of choices.

I'm a wood-working software engineer, not an EE, so..

I have one follow up question:

How can I calculate the watts that the transformer should be rated for? Is there a formula that I can use based on the amp requirements of the saw motor?

Thanks again!

Hi, Memory, if I may be so informal.

You wrote:

"I am not an EE . . . "

Have a Pro run a 220 line for your table saw specifically. Do not plug anything else into this circuit - ever.

The Wattage necessary should be stamped on a plate on the motor of the table saw.

I, too, am a woodworker.

/Ari (Orpheuse)

How about telling in what country you live in!!! Why is it a secret?????we could help you so much better!!!!

I am not an EE either!!!

Have you checked the motor plate for the option to rewire it for 110V? Most that I have seen are able to be changed and it is really straight forward. Just match up the correct color coded wires. There will be a higher amp draw but the watts should be about the same. Also make sure the breaker and wiring are rated for the higher amp draw. Do not change out a breaker to a higher rating if the wiring can not handle the load. I am not sure how much this would effect the HP rating of the motor if any.

If this is a new saw then this might alter or void the warranty. Check on that before hand.

Please point out any faults with my post.

Actually saw this done on a grand commercial scale - in a nursing home. As a young EE on my first job I was asked to survey a Mennonite nursing home for required upgrades in the early 70's. Since many old order Mennonites did not use electricity then, their maintenance staff was a bit short on electrical savy. They did just what this post is suggesting. If they needed 220VAC to run a piece of equipment, they would find two 110VAC circuits on different phases and use them with no additional protection for the circuit. Why they even managed to get some 3 phase running this way. The phase over loading and mismatch was astounding. I assume they just kept increasing the fusing on circuits until they would hold without tripping, and of course wire size was of no concern to them. They had THHN coated wires so hot the plastic was starting to melt.

Yes, this can be done as described - find 2 different phases and it will work - but please make it temporary, and don't increase the fusing to hold the circuit.

As long as the two phases come from the same source, it should work fine. As to why insualtion was melting there was another reason that has not been correctly found.....

But I would get an electrician to do it if you are not fit yourself in this area.....best is a purpose built socket, near to the fusebox and correctly fused for 3 phase. How many you use is then upto you!! (this assumes a 3 phase fusebox in the building concerned.)

Re: Device for Connecting Two 110 VAC to Make One 220 VAC

Three Choices: (1) Return the Unit for a 220 VAC Unit. (Not What Your Asking)

(2) Replace just the 110 vac motor for a 220 vac motor.

(3) Buy 1 to 2 Step transformer with the current rating Equal to the

Saw Motor. Connect the Lowside 110vac to the wall plug, the High

Side 220vac to the saw. With Volt Ohm Meter, measure the Input

Voltage & Output Voltage before switching on the Saw.

I definitely agree with Jraef and gave him another vote for GA. Have a 220 dedicated line installed for this purpose. Any other workaround is going to be more expensive, probably not safe and probably not legal. When working with electricity there is no substitute for doing it properly. Electrical Codes exist to ensure YOUR safety. Any time you do something differently you're putting not only your own life in danger but everyone else who may be in contact with your workaround.

Consider this - if you buy a transformer, how are you going to wire it up, where is the ground circuit, what type of enclosure will you use, what type of wiring will you use? Will you have it inspected by an electrical inspector? If you know the answers to these questions then you'll realize it's going to cost you more than a new 240 line.

Grae

Thanks you all for all the advice.

I will have a professional install a new line.

Greetings.

If your two outlets are fed from different sides of your breaker panel then you have 220 volts there already. If the outlets are off of the same breaker you don't.

If the outlets are off of two different circuits but on the same side of the breaker panel change one to the opposite side and you have 220 volts available.

Wiring in an outlet for 220v from the two 110v will give you the desired source for the installer.