220v from 2 x 110v plugs

[Duncan Horner]

Geez, I can't believe how many "the sky is falling" postings there are on this topic.

I understand what you're saying, and I know that there need to be specific circumstances in place for an accident to happen.

I also do not advocate running a table saw without a blade guard, even though you need to have certain circumstances in place for an accident to happen.

Would you endorse a first-time owner of a table saw tossing the guard? OP very clearly doesn't understand electrical theory, you can warn against the things that may hurt him, but that doesn't change the fact that he knows very little about the subject at hand.

Installing something potentially dangerous, even if not against code, can cause harm, maybe he has employees, maybe he'll let someone help him one day. I know of very few people that would assume male prongs of an extension cord to be inherently dangerous, so at the very least there's the potential for someone to forget they were warned, or perhaps not get warned at all.

If that's the case, his butt is in court, and he's in serious legal trouble.

That's my reason for not backing the idea. The sky is not falling, but life is expensive, and electrons are effective at ending them.

And just as an aside, try shorting 120V with a transformer in series, and tell me you didn't get more than 50mA before the transformer throttled the current. High impedance isn't a guarantee of low current. That's why motors draw high current when starting isn't it? Inrush current?

[Ed Bamba]

Ed,

Assuming (2) things:

• The circuit was wired with #12 and,
• The empty slot means you can put in a fullisize, 2-pole breaker (vs. the halfsize breakers), then

Yes - you can convert the circuit from 120v to 240v by replacing the single pole breaker with a 2-pole breaker. Reemmebr to reidentify the white/neutral conductor with some black tape or permanent marker to signify that it's a "hot" conductor.

Rob, thanks for clearing that up for me. I always wondered if that could be done if all the right parameters were in place.

[adam krause]

I see this is a very old thread but I'm in the middle of making a decision on this topic. I'm a commercial painting contractor and we also refinish hardwood floors. We just bought a brand new Clarke Floor Crafter belt sander that runs on 220. On a floor refinishing forum not unlike this one, a few guys said they have used this Sidewinder Power Cord to pull from (2) 110 outlets to get 220 into the machine while working in older buildings where there is no dryer or stove plug. I'm glad I stumbled across this forum because it seems like most of you say NO, NO, NO.
Question: Does anyone have any experience with this cord @ bottom of the page on the following link: http://www.ussander.com/products/?main=su&type=plug

[Mike Henderson]

I see this is a very old thread but I'm in the middle of making a decision on this topic. I'm a commercial painting contractor and we also refinish hardwood floors. We just bought a brand new Clarke Floor Crafter belt sander that runs on 220. On a floor refinishing forum not unlike this one, a few guys said they have used this Sidewinder Power Cord to pull from (2) 110 outlets to get 220 into the machine while working in older buildings where there is no dryer or stove plug. I'm glad I stumbled across this forum because it seems like most of you say NO, NO, NO.
Question: Does anyone have any experience with this cord @ bottom of the page on the following link: http://www.ussander.com/products/?main=su&type=plug

$455 for that cord!!!! Wow, that's absurd. All that cord does is take the two black (hot) wires from two 120V plugs and bring them out to the 240V connector. If you really wanted to do that, you could take two 120V extension cords and make your own for a lot less than $455.

As other people have stated, yes it's possible to get 240V in that manner but it's not all that safe. I wouldn't recommend it except in some life threatening emergency, and then by someone who really knows electricity and how buildings are wired.

Mike

[Art Mann]

I guess I am the only person who has actually done what the OP is proposing. Before I wired my shop, the only place to use my woodworking equipment when I moved in my house was in my garage. There was no 240VAC available in there and I didn't want to install a 240 VAC outlet just for temporary use. Since I was the one who wired the house, I was aware of two plugs that were adjacent and on different hot legs. I simply created a "Y" cable that accessed the two hot legs. It worked for me for several months before I wired and completed the shop. I sometimes disagree with Rick on electrical issues but this time I think he is absolutely right. In order for this setup to be dangerous, you would have to do something stupid or allow someone else access to the wiring who doesn't understand what is going on. I am not saying this is the best thing on a permanent basis but it will work and it isn't dangerous if you do it right and restrict access to other people.

[John Densmore]

I agree with the general consensus of the replies, don't try this at home.

[Julie Moriarty]

Ok, so I'm going to preface this question with a statement... I am a carpenter, not an electrician, so please dont laugh if I'm completely off base.

I am about to rent a shop space, and buy my first Bandsaw, Jointer and Planer. Currently I am limited to 110v outlets, and the breaker panel is in the space next to mine, so I dont have access to it, and I would not be allowed to run the new cables either. I would like to buy some higher quality equipment, that requires 220v. Is there someway that I could build a 220v extension cable that plugs directly into two seperate 110v outlets?

Thanks for any help that you can offer.

(It's taken me a year to find this place, so waiting for a place with 220v isnt an option.)

In today's world, it's rare that the electrical service feeding a building is single phase, 120V. So odds are the service feeding the building you are in is 120/240V, unless it's in a commercial area where you might have 120/208V. The idea you can take (2) 120V receptacles to tap into and come out with 240V (or 208V) could work if the service is 120/240V or 120/208V AND you tap opposite legs of the service. If you don't know what I'm talking about, call someone who does and let them do it right.

However, if you start finding whatever wires you can to make things work, you may be creating a nightmare for yourself. You've posed your electrical questions on a woodworkers forum. Why? Just because we use electrical woodworking equipment does not make us electrical installation experts. That you asked the questions you did tells me you don't understand how things work in the electrical world. FWIW, I am an electrician, now retired, and looking forward to early-bird specials and grandchildren wearing me out.

You can probably get what you need from the service that feeds your shop. Only the ampacity of the service and the capacity of the panel would limit you. But you really should consider calling in an electrician. He or she will be able to wire your shop with practically anything you need. And you can offer your talents in carpentry in exchange for their electrical talents.

[Art Mann]

I was assuming this shop space was temporary since the OP was reluctant to approach the landlord about new wiring. If that isn't the case and this is a permanent installation, then having a permanent 240VAC outlet pulled and installed is the rational course of action.

[Gary Salisbury]

Don't worry, you are not the first person to ask this. It just won't work. Trying to get 220 from two 110 outlets is like connecting two 90psi hoses and expecting 180 psi.

Sorry Allan but you made me laugh with the analogy. You can get 240VAC from two 120VAC if each 120VAC circuit is on a different phase. To prove my point, just open up your circuit breaker panel and measure from each phase to neutral = 120VAC. Now measure between the two phases - 240VAC. Right? Now, is it legal according to building code? Not in any city I have ever been an electrician in because the breakers are not bound to each other via a physical trip bar on the breakers as a 240VAC circuit has.

[Gary Salisbury]

Ok, so I'm going to preface this question with a statement... I am a carpenter, not an electrician, so please dont laugh if I'm completely off base. I am about to rent a shop space, and buy my first Bandsaw, Jointer and Planer. Currently I am limited to 110v outlets, and the breaker panel is in the space next to mine, so I dont have access to it, and I would not be allowed to run the new cables either. I would like to buy some higher quality equipment, that requires 220v. Is there someway that I could build a 220v extension cable that plugs directly into two separate 110v outlets? Thanks for any help that you can offer. (It's taken me a year to find this place, so waiting for a place with 220v isnt an option.)

If you are considering new equipment, then consider a vendor who provides dual voltage equipment that runs on 120VAC or 240VAC simply by rewiring the motor. My JET bandsaw, planer, shaper, sanders, and a number of other JET tools run dual voltage. Unfortunately, my JET cabinet saw does not because the horsepower of the motor is too high. I think (but do not know for sure) that the limit for dual voltage motors is typically 1½HP which draws 20 amps at 120VAC.

[Art Mann]

Sorry Allan but you made me laugh with the analogy. You can get 240VAC from two 120VAC if each 120VAC circuit is on a different phase. To prove my point, just open up your circuit breaker panel and measure from each phase to neutral = 120VAC. Now measure between the two phases - 240VAC. Right? Now, is it legal according to building code? Not in any city I have ever been an electrician in because the breakers are not bound to each other via a physical trip bar on the breakers as a 240VAC circuit has.

What you plug into a wall outlet is your business and inspectors don't care. No inspector will ever even see it unless someone calls them out there and then they will be very reluctant get involved. That isn't what inspectors do, at least where I live.

[Art Mann]

If you are considering new equipment, then consider a vendor who provides dual voltage equipment that runs on 120VAC or 240VAC simply by rewiring the motor. My JET bandsaw, planer, shaper, sanders, and a number of other JET tools run dual voltage. Unfortunately, my JET cabinet saw does not because the horsepower of the motor is too high. I think (but do not know for sure) that the limit for dual voltage motors is typically 1½HP which draws 20 amps at 120VAC.

Grizzly sells several bandsaws and tablesaws that are rated 2 hp and will work on a dedicated 20A circuit. 120VAC at 20A is equivalent to 2400 watts. That is equivalent to 3.2 hp. Even after subtracting out line losses and motor inefficiencies and power factor current, you can still run a 2 hp motor on 120VAC in many cases. I am speculating that stationary tools for home use are usually limited to 1.5 or at most 1.75 hp due to the fact that home wall outlets are usually rated at 15A.

[Gary Salisbury]

Grizzly sells several bandsaws and tablesaws that are rated 2 hp and will work on a dedicated 20A circuit. 120VAC at 20A is equivalent to 2400 watts. That is equivalent to 3.2 hp. Even after subtracting out line losses and motor inefficiencies and power factor current, you can still run a 2 hp motor on 120VAC in many cases. I am speculating that stationary tools for home use are usually limited to 1.5 or at most 1.75 hp due to the fact that home wall outlets are usually rated at 15A.

Thanks Art. I didn't know that.

[Mike Cutler]

I see this is a very old thread but I'm in the middle of making a decision on this topic. I'm a commercial painting contractor and we also refinish hardwood floors. We just bought a brand new Clarke Floor Crafter belt sander that runs on 220. On a floor refinishing forum not unlike this one, a few guys said they have used this Sidewinder Power Cord to pull from (2) 110 outlets to get 220 into the machine while working in older buildings where there is no dryer or stove plug. I'm glad I stumbled across this forum because it seems like most of you say NO, NO, NO.
Question: Does anyone have any experience with this cord @ bottom of the page on the following link: http://www.ussander.com/products/?main=su&type=plug

Adam

It seems pretty expensive for a simple cord, but you are operating a business, so if you were to cobble one together and hot rod it into a house and cause damage, I can see that your liability would increase.

Electrically, there is nothing wrong with that sidewinder setup. Used correctly it will work just fine. The problem is finding two outlets, on seperate circuits, and opposite poles, that close together. The kitchen would be the most logical place, but depending on how old the house is and how many years, and code changes, have occured doesn't make it a guarantee. I definitely would want to know that my machine was the only load on those two circuits.
I have a friend that does similar work and he has a plug that goes into the dryer outlet, or the electric range. Typically he's the only one inthe house when this goes on so that's what he uses.

[Mike Cutler]

Grizzly sells several bandsaws and tablesaws that are rated 2 hp and will work on a dedicated 20A circuit. 120VAC at 20A is equivalent to 2400 watts. That is equivalent to 3.2 hp. Even after subtracting out line losses and motor inefficiencies and power factor current, you can still run a 2 hp motor on 120VAC in many cases. I am speculating that stationary tools for home use are usually limited to 1.5 or at most 1.75 hp due to the fact that home wall outlets are usually rated at 15A.

Art

The motor on my General International, 50-220C, hybrid, tablesaw, is rated for 2 hp. It came with a pre-wired, moulded , 120vac, 15 amp plug. It's got, or had, the UL cert tag right on the cord.