220v from 2 x 110v plugs

[Todd Pretty]

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.)

[Richard Blaine]

A non-three phase service uses two hot wires (legs). Both wires are 110 volts. In order to achieve 220 volts, you need to tap into both legs.

While I can't say that both legs are not present in your space, I'm willing to bet that it is a code violation to combine both legs outside of the breaker box. The first think that comes to my mind is that the breakers would act independently leaving you with the possibility of having half of your power trying to run the equipment.

[Allan Froehlich]

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.

[Duncan Horner]

Depending on the age of the building concerned, he might end up with 208V, if it's a 3-phase panel.

If it was a single phase supply, AND you had 2 legs to tap into, it is *theoretically* possible.

Further to Richard's concerns, you'd have real safety issues involved. If one circuit breaker tripped, and you were to unplug the cord to troubleshoot, the male pins of that cord would be live with the other leg's 110 volts. Major hazard. I'm pretty sure an inspector would tell you to take it out once he got done shouting at you.

You'd be effectively making something analogous to a 110V open neutral situation, whereupon the neutral end coming from the equipment is at line voltage.

[Myk Rian]

Is there someway that I could build a 220v extension cable that plugs directly into two seperate 110v outlets?
Absolutely not!!!

[Anthony Whitesell]

Could you...Yes...if you can find two outlets that were on different legs within the panel (not going to be an easy task). Should you...NO WAY...it violates so many codes and creates huge electrical hazards that we couldn't list them all. The first of which is the lack of the single trip breaker, a 220V breaker trips and disconnects both hot legs if either overloads. In this situation, one breaker could trip but not the other, then you would only have 110 to the motor and it would fry. Adios, 220V xHP motor.

You'll need to either stick with 110V, find way to get some 220 lines run, or wait for another place. I'm sorry for the bad news.

[Rob Russell]

Todd,

The answer to your question is that Yes, you could build such an extension cord.

There are problems that you could run into and, as Duncan noted, you would need to know if the service in the building is 3-phase or not. As noted, you could trip 1 of the 2 breakers and that wouldn't be good.

Electrically, it could work. The service would need to be standard 120/240v single-phase. You would need to be able to locate outlets on 2 circuits that were both on different breakers and on different busses in the panelboard.

= = = = = = = = = = =

My recommendation is that you hire an electrician and have a 240v, 20 amp circuit installed in the space that you're renting. It's safer in the long run. If you're paying for the electrician, I would think that the building owners shouldn't have an objection to a licensed sparky doing the work.

[Rob Russell]

Should you...NO WAY...it violates so many codes and creates huge electrical hazards that we couldn't list them all. The first of which is the lack of the single trip breaker, a 220V breaker trips and disconnects both hot legs if either overloads. In this situation, one breaker could trip but not the other, then you would only have 110 to the motor and it would fry. Adios, 220V xHP motor.


Sorry, but I believe that what you posted is incorrect.

First, the electrical codes are designed to protect the building. There is nothing in the codes that applies to what you plug into the circuits even if we look at it and say "bad idea".

Second, as soon as one of the 2 breakers tripped - the motor would stop. An analogy is using a single pole vs. double pole switch for a 240v motor. Either way the motor will stop.

[Rollie Meyers]

What you are proposing is a good way for people to get hurt/killed, if one attachment plug is removed, 120 volts can back feed through the equipment on the load side energizing the prongs of the plug that was removed,my advice is hire someone qualified to do the work.


This is the stuff that becomes fodder for the Darwin Awards website.

[Sam Layton]

I am with Anthony, NO WAY. There is a reason that 220 brakers must be connected so if one trips the other trips... There is always ways to jerry-rig something to make it do what you want it to do. However, there are some things that you should not try to jerry-rig. I agree you need 220 for most tools. I would try to find another space witrh 220.

Sam

[David G Baker]

Todd,
The two separate 110 plugs are probably on the same circuit and if so it will be as Allan F. described with the two 90 pound air lines combined will still be 90 pounds of air not 180 PSI.
My suggestion is for you to buy 110 volt equipment or make arrangements to get a 220 volt tap off of the power panel. There is also the possibility that the plugs that are available to you are 15 amp plugs protected by a 15 amp breaker and this is not enough to run any heavy duty equipment.
The only other option is to get back in line for another shop because if you don't have access to the needed power you should forget the idea. You could always buy a heavy duty generator that will handle your power requirements.

[Rob Luter]

First off - NO

Now technically speaking, a normal single phase (residential) system has two hot legs, a neutral, and a ground. Voltage between the two hot legs is 230v, and between either hot leg and neutral 115v. You could theoretically have a situation where two outlets remote from one another might be on seperate hot legs and do some fancy wiring of cords and get real lucky and.............

On second though, NO

[Rod Sheridan]

Todd,
The two separate 110 plugs are probably on the same circuit and if so it will be as Allan F. described with the two 90 pound air lines combined will still be 90 pounds of air not 180 PSI.
My suggestion is for you to buy 110 volt equipment or make arrangements to get a 220 volt tap off of the power panel. There is also the possibility that the plugs that are available to you are 15 amp plugs protected by a 15 amp breaker and this is not enough to run any heavy duty equipment.
The only other option is to get back in line for another shop because if you don't have access to the needed power you should forget the idea. You could always buy a heavy duty generator that will handle your power requirements.

Actually if you use two wires from the same pole you get zero volts differential, not 120 volts, since they are in phase.

A 15 ampere breaker is large enough to run shop equipment, I have a General 650 that only draws 12.5 amperes (3HP) so it runs from a 15 ampere circuit.

Same for my General Shaper, Bandsaw, Hammer A3-31 planer etc.

Regards, Rod.

[Chris Padilla]

Todd,

I think you have the idea that to do this, even if it "works", is a bad idea in general. So I see some options:

(1) Try your new equipment with what you've got and see if it'll work.
(2) Talk to the landlord about getting you some 240 V in your space...offering to hire a licensed electrician might get you what you want.
(3) Inspect the breaker box and/or outlets in your shop...could they be possibly upgraded from 15 A to maybe 20 A? If they are run with #14, you are SOL (possibly...can new wires be EASILY pulled?)...if they were run with #12, then you just gained another 5 A on your 120 V circuits and it may help in situation (1) over situation (2).
(4) Maybe a 240V plug could be placed right at the breaker box and you could run an extension cord to your shop? This one may have issues as well since it is more or less a "permanent" extension cord but it could be the least expensive.

I'm curious. If you don't have direct access to the breaker box, what happens if you trip a breaker in your shop? Will it take an hour or two to get someone to reset the breaker? Sounds like a pain to me. You may wish to negotiate some reasonable access to the breaker box in your lease agreement....

[Chip Lindley]

.........and the breaker panel is in the space next to mine, so I dont have access to it.........(It's taken me a year to find this place, so waiting for a place with 220v isnt an option.)

Todd, KEEP Looking for workspace! What if you trip a circuit?? No access to even reset the breaker Next Door? Hmmmm... Keep Looking!

[Howard Acheson]

Here is what you want to use:

http://www.quick220.com/220_volt.htm

It allows you to use two 120 volt circuits to develop 240 volts. Be sure the amperage and wattage parameters are what you need.

[Jason Beam]

Here is what you want to use:

http://www.quick220.com/220_volt.htm

It allows you to use two 120 volt circuits to develop 240 volts. Be sure the amperage and wattage parameters are what you need.


Well fancy that ... someone thunked of the safety problems and made a product for it.


To make sure this isn't misinterpreted - this nifty little device will ONLY ONLY ONLY work if you have more than one 120v circuit feeding your space. It will NOT work if both outlets are on the same circuit. Read the FAQ before plunking down $150 bucks!!!!

[Anthony Whitesell]

Based on that little do-hickey, it would not be hard to make something similar and better.

What if you took a small subpanel, fed it from two 120V circuits (giving two hots, a neutral, and a ground), installed a 220V circuit breaker (giving you the trip-one-hot trip-both-hots requirement), and attached a suitable 220V recepticle. Thoughts? I think it would run you a lot less that the Quick 220 at $150.

[Jason Beam]

Not quite - the thing missing is a sensing mechanism to completely cut off power if either of the 120v plugs are pulled out. That gizmo claims to do this. You'd need some kind of relay setup or sensing circuit to accomplish the same.

[Rod Sheridan]

Not quite - the thing missing is a sensing mechanism to completely cut off power if either of the 120v plugs are pulled out. That gizmo claims to do this. You'd need some kind of relay setup or sensing circuit to accomplish the same.


Exactly, it's the auto disconnect that's needed......Rod.

[Anthony Whitesell]

True. True. I missed that. But two high amperage contact 120V coil relays would do the trick. With the right subpanel, it could all fit in there. But now I think you'd be close to the price of the pre-made gizmo. I didn't see in their literature about overloading and which breaker(s) trip or if the 'box' has it's own breaker. But then again, based on the design, if only one breaker trips, then the light goes out and power to the equipment is lost. So I guess that's good too.

[Rob Russell]

But two high amperage contact 120V coil relays would do the trick.

I'd think that you'd need a relay/contactor with a 240v coil where both hot legs flow through the relay/contactor. Using a 240v coil means that if either 120v leg drops out the relay/contactor will open.

I'd have to think about it for a minute in terms of how I'd wire it with (2) 120v coil relays, but it would certainly complicate things.

[Bob Wingard]

No theory here .. it CAN be done, and done SAFELY, although, probably not in your situation.

I had a friend who wired all of his duplex recepts. in his shop in such a way that the upper outlet was on one breaker, and the lower outlet on another, fed from the other leg of the box. He made up several pigtails that had two 120V plugs and a single 240 recept. n His thought was that he could provide 240V anywhere in his shop with that setup without hard wiring any 240V recepts.

He asked the inspector first, and although he didn't like the idea, he said it was not a code violation. As was stated earlier, the inspection only dictates what goes on behind the wall covering, NOT what you plug into it.


<<<__ Bøb __>>>

[Chris Padilla]

I had a friend who wired all of his duplex recepts. in his shop in such a way that the upper outlet was on one breaker, and the lower outlet on another, fed from the other leg of the box. He made up several pigtails that had two 120V plugs and a single 240 recept. n His thought was that he could provide 240V anywhere in his shop with that setup without hard wiring any 240V recepts.

Yep, that is called Edison wiring or multi-wiring. I did the same except with two duplex receptacles in a double-gang box: one is a "red" hot and the other is a "black" hot. :)

[Duncan Horner]

Chris: Yet you thought it was a bad idea in your first reply?

Same setup as propositioned by OP, and just as dangerous.

Good point about breaker access however, I'm pretty sure the code *does* say something about the only disconnects being located in an inaccessible location.

[Jason Beam]

No theory here .. it CAN be done, and done SAFELY, although, probably not in your situation.\


WRONG.

It can NOT be done safely that way. FLAT OUT PERIOD NO. NO NO.

I ask you - pull one of those plugs and put a meter on it and tell me it's safe.

No disrespect, but that is very dangerous advice.

Unless something is placed on that cord to prevent the MALE ends of either 120v plug from being live, IT IS FLAT OUT NOT SAFE

I ask anyone reading this thread now to be very sure you understand why this is not safe if you're going to attempt this technique.

[Todd Pretty]

Wow... first off, thanks for all of the great information, I didn't even know if I'd get a single response... alot of "hot" ideas here


Based on that little do-hickey, it would not be hard to make something similar and better.

What if you took a small subpanel, fed it from two 120V circuits (giving two hots, a neutral, and a ground), installed a 220V circuit breaker (giving you the trip-one-hot trip-both-hots requirement), and attached a suitable 220V recepticle. Thoughts? I think it would run you a lot less that the Quick 220 at $150.


This is more or less along the lines of what I was originally thinking... and I knew I was missing something... now that I know the safety concerns of backfeeding one tripped 110v circuit into the other, I realize that wont work.... unless.... I just thought about this... what if I install a capacitor on each of the hots on the 110v leads... shouldn't that stop the flow of power to the untripped circuits? Then there is no need for a relay or comlicated wiring... of course I have no idea how much a 110v 15amp capacitor would cost.

[Todd Pretty]

Here is what you want to use:

http://www.quick220.com/220_volt.htm

It allows you to use two 120 volt circuits to develop 240 volts. Be sure the amperage and wattage parameters are what you need.


That is awesome.. I'll definitely look into that more.

[Tom Veatch]

Jason, check me on this, please. I'm trying to be sure I understand why it's dangerous.

You've got two power cords going to the load, each plugged into separate 120v sockets. One power cord gets unplugged while the other is still plugged into a live circuit. Is that the scenario we're looking at?

If so, that's the same situation as a single power cord with a plug on each end where one end is plugged in and the other just laying out on the floor. In that case, the "hot" prong of the unplugged end is directly connected to the live "hot" and exposed for all the world to see and touch. Really no different than sticking a knife into the hot side of any live receptacle.

Am I understanding it correctly?

[Tom Veatch]

...what if I install a capacitor on each of the hots on the 110v leads... shouldn't that stop the flow of power to the untripped circuits? ..

If it were DC, the capacitor would stop the flow once it were charged up, but a capacitor will pass AC current. The smaller the capacitance, the higher the effective resistance at a given cycles per second but you'll still get some current flow for any finite value of capacitance.

[Duncan Horner]

Ok, a capacitor will do nothing. You shouldn't even be thinking about these modifications if you think it will. 50 milliamps is all it takes to kill a person stone dead. Don't take chances.

Do what's right and safe. Take a pass, or use a UL Listed device as mentioned above (if it even has a listing).

[Duncan Horner]

Really no different than sticking a knife into the hot side of any live receptacle.

Am I understanding it correctly?

Yes. Male prongs with 120V on them.

[Rob Russell]

I'd like to respond generically to a bunch of the posts in this thread.


I don't think it's a good idea to tie (2) 120v circuits together to make a 240v circuit unless you know what you're doing. The gizmo posted sort of makes this foolproof.
There is NO NEC PROHIBITION to doing this. The NEC (and locally adopted modifications to the NEC) apply to the wiring in the building - NOT what you plug into the receptacles.
It is true that, in extreme circumstances, one could create a potential where a single hot leg transmitted current through a load to energize a pin on an opposing plug. I'd say that likelyhood is pretty slim. The gizmo posted would prevent this from happening. You could also build a device to do this.
I would still go back to my final advice and have an electrician install a circiut. If, as suggested, you can get the building owner to agree to installing a subpanel in your workspace, I'd pay to have that done.

To all of the posters who have said that tying (2) 120v circuits together can not be done - shame on you. Your statements are electrically wrong. Still, doing it "SAFELY" means understanding what's going on with the wiring, which is a big IF and not something I would trust a typical non-electrician/homeowner to be able to do safely. That does not mean that tying the 2 circuits together safely can't be done.

Please note that I'm not advocating tying (2) 120v circuits together to create a 240v circuit.

As I posted earlier, the best route is an electrician and installing a circuit or subpanel in the workshop.

[Jason Beam]

Jason, check me on this, please. I'm trying to be sure I understand why it's dangerous.

You've got two power cords going to the load, each plugged into separate 120v sockets. One power cord gets unplugged while the other is still plugged into a live circuit. Is that the scenario we're looking at?

If so, that's the same situation as a single power cord with a plug on each end where one end is plugged in and the other just laying out on the floor. In that case, the "hot" prong of the unplugged end is directly connected to the live "hot" and exposed for all the world to see and touch. Really no different than sticking a knife into the hot side of any live receptacle.

Am I understanding it correctly?

Tom, exactly right. That's precisely the danger of just throwin together an extension cord as has been advocated. You need to KNOW that no metal can be touched that will hold a charge. It's terribly improper to suggest that such an idea is safe.

[Dan Friedrichs]

Are you sure you need 220V, even? Most motors wired for 220V can be changed to 120V easily. Perhaps you have heavy gauge wires and short runs to the breaker box, in which case, the 220V might not gain you anything.

[Rick Christopherson]

Geez, I can't believe how many "the sky is falling" postings there are on this topic. It would seem that those people screaming the loudest don't really understand the topic. Shame. Instead of throwing your arms up into the air and screaming, offer some advise. (I guess Rob's last posting kind of stated what I mean, but I didn't see it until I was nearly finished.)


If the building has a 120/208 3-phase supply, it will make no difference whether he hires an electrician or not, he is still going to only get 208 volts from any receptacle, so this is completely off topic.
If one circuit breaker trips, the tool just shuts off. It doesn't get half the power, and it doesn't pose any threat to the operator or circuit.
The only danger to doing this is a backfed voltage, and even that is only an issue if someone unplugs the cord.
Before there is a problem with backfed voltage, three things need to happen. If one of those three items is missing, then there will be no problem.




A tool must be plugged into the 240 V receptacle. No tool; no backfeed.
The tool must have a non-switched load, or the switch left in the On position. Most tools with magnetic starters that do not have low voltage controls will automatically cut out, and there will be no potential for a backfed voltage. Most retail grade woodworking tools use mechanically driven magnetic starters, and when they are off, there is no path for a backfeed. Very few of these tools will have the low voltage controls with a transformer, and even still, the transformer is a high impedance path.
And here's the biggie...someone needs to unplug one of the power cords from the wall and touch the exposed prong. If you don't unplug it, then there cannot be a problem.

Obviously this isn't something you want to do willy-nilly, nor should it be considered a long-term solution, but it will not blow up the shop either. Under other circumstances, I would probably be cautioning you more, but that has been done quite enough already.

Oh, one thing that no one has mentioned is that this concept will not work if the outlets are GFCI protected. The GFI will trip because no current will be recorded in the two neutrals.

[Ed Bamba]

If I may, can I pose this question? Can a 20A, 110V outlet be converted to 220V? That is provided that it is the only outlet on that circuit, and that there is an empty slot next to the breaker at the breaker box. Will the existing 120V wiring be too small for the 220V power?

Ed

[Rob Russell]

If I may, can I pose this question? Can a 20A, 110V outlet be converted to 220V? That is provided that it is the only outlet on that circuit, and that there is an empty slot next to the breaker at the breaker box. Will the existing 120V wiring be too small for the 220V power?

Ed

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.

[Chris Padilla]

Chris: Yet you thought it was a bad idea in your first reply?

Same setup as propositioned by OP, and just as dangerous.

Good point about breaker access however, I'm pretty sure the code *does* say something about the only disconnects being located in an inaccessible location.

Yes, I still think it is a bad idea. All I was responding to was the multi-wiring...nothing else.

[Tom Veatch]

... That is provided that it is the only outlet on that circuit, ...

That implies that maybe only one outlet is allowed on a 240v circuit. That is not the case. You can have multiple outlets on a 240v branch circuit just like you can have multiple outlets on a 120v branch circuit.

[Rod Sheridan]

Tom, I think he meant to make sure that you don't accidentally connect other devices on the circuit to 240V.

Regards, Rod.

[Todd Pretty]

If it were DC, the capacitor would stop the flow once it were charged up, but a capacitor will pass AC current. The smaller the capacitance, the higher the effective resistance at a given cycles per second but you'll still get some current flow for any finite value of capacitance.


I meant a diode... not a capacitor... a capacitor would probably make the system more lethal as it would built up a charge... that's what I get for reading late at night. Isn't a diode installed in a circuit to limit the flow of power to a single direction?

[Todd Pretty]

Jason, check me on this, please. I'm trying to be sure I understand why it's dangerous.

You've got two power cords going to the load, each plugged into separate 120v sockets. One power cord gets unplugged while the other is still plugged into a live circuit. Is that the scenario we're looking at?

If so, that's the same situation as a single power cord with a plug on each end where one end is plugged in and the other just laying out on the floor. In that case, the "hot" prong of the unplugged end is directly connected to the live "hot" and exposed for all the world to see and touch. Really no different than sticking a knife into the hot side of any live receptacle.

Am I understanding it correctly?

In one scenario you have a female end of the plug that is hot, and you would actively have to "stick a knife in it" or something else to ground the charge.

In the second scenario you have an exposed male end of the plug, which by all convention and tradition, if it is exposed, should not have any charge in it... and could easily be touched.

[Todd Pretty]

Well after much heated discussion, while potentially feasible, it doesnt seem like the best idea. I'll talk to the landlord, and see about getting a 240v plug installed, even if it is at my cost.

[Duncan Horner]

I meant a diode... not a capacitor... a capacitor would probably make the system more lethal as it would built up a charge... that's what I get for reading late at night. Isn't a diode installed in a circuit to limit the flow of power to a single direction?

AC current means Alternating Current. Meaning half the time it flows one way, half the other. A diode would only stop it half the time, and would stop AC motors from working at all. An even worse idea than the capacitors lol

[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 (https://youtu.be/hsfgwEUXtTc?t=3m33s).

[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.

[Frank Pratt]

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

That thing is an abomination, should never see the light of day and it cannot possibly be legal. Think about it for a minute; what happens if 1 of the 120V cord ends gets unplugged when the machine is turned on? That's right, you will have a 120V live prong exposed & waiting to zap someone because it's getting back fed from the other circuit through the machine. Even if the motor is not running but the machine has electronic controls that are in the circuit it can be enough to deal a fatal shock.

I hate to even think of the trouble you would be in if you brought that on to a job site & someone got hurt.

It would be possible to build such a thing with protection relays in it to disconnect everything if one of the sources is disconnected, but the website doesn't make any references to that.

[Julie Moriarty]

There have been numerous times one of the other trades comes to us on a job with some cobbled together thing and asked one of us to hook it up for them so they can run one of their machines. Usually, I've had to make some alterations to the setup like doing some rewiring or make something from our job stock. Some of these contraptions were one moment from disaster yet the owner of the machine would say, "I've hooked it up on other jobs and it worked fine." http://i867.photobucket.com/albums/ab233/jules42651/Emoticons/eusa_doh_zps03302b01.gif

That Sidewinder thing has almost all the cord length on the 120v side. I can just see now... someone plugging one end into an outlet then going from one outlet to the next with the other end until they got 240v. And then saying, "OK! We're good to go! Let 'er rip!""

http://i867.photobucket.com/albums/ab233/jules42651/Emoticons/popcorn-1_zps2be5c0dd.gif

[Mike Henderson]

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.
I think that's pretty unusual, Mike. 120V times 15 amps is 1,800 watts. A HP is about 750 watts but there are losses in the motor, plus a power factor issue. In my experience a good efficient motor will require at least 1,000 VA (volts times amps, which accounts for the power factor losses) and perhaps even more than 1,000 VA per HP.

And if it really will produce 2 HP it seems that it would be pretty easy to exceed 15 amps when it's producing that 2HP.

Mike

[Scott Hearn]

Somebody mentioned it before but a 5000W or bigger generator would work if you just need to run you 220V machines to make some cuts and then go back to your 110V tools. Almost all generators in this class have a 220V 30amp twist lock plug. Heavy usage of the 220V stuff would make this option not too desirable due to fuel cost and hassle factor, but it is an option.

[Dennis Aspö]

You could apparently do what the OP wants in Canada, but not necessarily the US.
http://woodgears.ca/bandmill/misadventure.html

[Mike Cutler]

I think that's pretty unusual, Mike. 120V times 15 amps is 1,800 watts. A HP is about 750 watts but there are losses in the motor, plus a power factor issue. In my experience a good efficient motor will require at least 1,000 VA (volts times amps, which accounts for the power factor losses) and perhaps even more than 1,000 VA per HP.

And if it really will produce 2 HP it seems that it would be pretty easy to exceed 15 amps when it's producing that 2HP.

Mike

Mike

I actually don't think it's 2 hp personally, something less in all probability, but that is how the motor nameplate data reads.
I was surprised it came prewired.