220 Power from two 110 volt sources

[Jim M]

I have always thought of doing this but wonder if it's feasable... in an emergency situation where 220 is needed to run a tool etc for a short burst of time... Since 220 is made up of two 110 volt legs. What would be wrong ( electrical codes aside as this is just a theory) with wiring up a portable

220 volt receptacle with two 110 volt cords comming out of it with male 110 volt plugs? This way a person could plug in each 110 volt plug to seperate 110 volt receptacles making sure they are on different breakers..? This in my opinion would make a very safe easy way of using 220 volt power in a jam.

Again...I am just looking at the theory part of it... Thanks...Jim

[Doug Miller]

You could buy or rent a generator...

That's a backward way of looking at it.

What would be wrong with it is that you'd have live, exposed contacts on each cord. Dangerous as hell. Why do you suppose that receptacles are *female*?

Not only different breakers, but different breakers on opposite legs of the

220V service.

If you have access to the breaker panel... why not install a normal 220V breaker and a 220V receptacle?

You may be the only person who thinks that's safe.

[Matt]

Are you saying - put male plugs on a generator, and then plug them into your house receptacles?

[zxcvbob]

It's not as bad as you think. What he is describing has female on one end and 2 males on the other. If there is a 240V load plugged in and turn on at the female end, when you plug in one male plug, the other male plug is energized. If you plug the males in first, you don't have exposed energized contacts at any point during the hook-up.

Still, it would be a *lot* better to install a 240V recepticle somewhere and make a proper 240V extension cord.

Bob

[Matt]

Wouldn't this mean that his whole house would be fed through breakers _backwards_? Do breakers care which end the juice is coming in from?

Wouldn't there also be some issues with the neutrals as well? I know nothing of wiring generators, but it seems like tying the house neutral to a generators output would cause some problems.

Another curious twist (to me anyway) would be if he plugged the male plugs into a female receptacle which was miswired (hot/neutral reversed).

And what would REALLY be neat to see is what happens if the main isn't shut off and then utility power is restored.

I'd pay to see that.

[Jim M]

[default]

If you need 220V, you probably also need more than 15 amps, which means that even if you find the right outlets, you're probably going to blow both breakers.

[Matt]

I guess what I don't understand is where is the electricity coming from that you want to produce? In other words - if you already have 2 hot

120v legs, why do you need to create a 220 v outlet in the first place...?

I think I _might_ understand what you are saying though - but I'm not sure. In any event, to produce 240 v, you need not only 2 120v legs, but two 120v legs which (someone please correct me on this) are 180 degrees out of phase.

In other words, lets say you had a 120v breaker, with a black wire coming off of it.

Now, you hook another black wire to the same breaker, and you now have two 120v leads, when each is measured to go ground.

Now, measure the voltage between the 2 black wires.... 0. Man You are confusing me!

[Jon Hutchinson]

[Ignoramus21190]

As a practical matter.

First, the OP has so little knowledge of electricity that I advise him to not attempt this.

What he is proposing can be done if the two receptacles are fed from opposite legs of the breaker.

There is no need for a neutral in a 220v circuit.

It is indeed dangerous, but sometimes there could be a genuine need to do it. Like if he bought some military surplus 220V items that he wants to test and then resell on ebay.

I would suggest to check if there are better sources of 220V in the house, such as electric range or dryer. One could then buy a plug and put a fuse in the wire.

I agree with everyone else who said to do it the proper way. That is, in fact, what I am now doing, getting a nice 220/110v subpanel in the garage.

i

[Mark]

No, just the one breaker he is backfeeding through. The remainder of the breakers will work in the normal fashion.

Oh man. That could be scary....

I've been using a very similar setup for the last 15+ years. I only need to use it about once a year, but it's a lifesaver when I need it.

I flip the main, plug in my dual male pigtail to a 30A unused dryer circuit and then run cable out to the generator for the 1/2 day that it's needed.

[Matt]

Got it...!

Thanks..... I'm a bit hungover this AM. And tired.... the nephew spilled a gallon of gas in the garage last night; spent all night cleaning and waiting for my house to explode..........

[Jon Hutchinson]

[toller]

There is actually a commercial product that does this; so yes, it does work (assuming your two 120v sources are oppposite legs)

If you used it temporarily, I suppose it might even be legal. Permanent use would be improper because the breakers are not tied together.

[John Harlow]

AC breakers "backfeeding", eh?

Are you even aware what AC stands for?

Besides, the guy is not suggesting *powering* the house anyway.

[Jim M]

"John Harlow" < Wrote

I was wondering why the previos poster was going on about powering up a house... I didn't want to power up a house with this....perhaps use the house as a source for the power yes.......

[Beachcomber]

It's not just "different" breakers. If you are looking for 240 volts, you need to find the hot wires of two outlets that are on different breakers (circuits) and different legs (180 d. difference) on your service panel.

One easy way of doing this is with a voltmeter and a two extension cords coming from outlets that you know to be on different circuits. If you measure the voltage between the two hot slots (the smaller slot on the left when the ground is below - if your house is wired properly), you should measure EITHER 120 V. or 240 V. (or something close). If your house is balanced properly, the probability of getting either voltage is 50-50 for any two circuit souces.

Keep in mind that that circuit breakers are going to be limited to either 15 or 20 amps, while getting your 240 volts.

I don't recommend to do what you are doing. A big safety issue is that the two breakers giving you your 240 Volts are not ganged, as are other 240 volt circuits in your house. For example, if your dryer circuit trips, BOTH legs are disconnected. This is to protect you from killing yourself by disconnecting all possible hot sources to the appliance. You have no such protection with your jury-rig system.

Beachcomber

[Matt]

Sorry Jim..... I completely missed what you were trying to accomplish.

[default]

Or you could use one of those arcane devices known to the illuminati as a transformer.. but what fun would that be?

--Goedjn

[Jim M]