[css28]

Disregarding the wisdom of the ultimate solution, you can use a voltmeter (AC volts readout of a multimeter will work) and measure the voltage between the hot terminals of the two specific outlets.
This would be the short blade in each of the outlets. If you see zero volts, they're on the same leg of the house circuits.

 

[ghostgs1]

I think the simplest way is to look at the breaker panel and select a breaker on each side. You can double check that they are the circuits that they are marked, by turning off the breaker to verify the current is no longer present. This may work ok for you, but you may find the circuits are separated by a bit. Be sure you use heavy extension cords, at least 12 gauge.

 

[ClarksonCote]

Disregarding the wisdom of the ultimate solution, you can use a voltmeter (AC volts readout of a multimeter will work) and measure the voltage between the hot terminals of the two specific outlets.
This would be the short blade in each of the outlets. If you see zero volts, they're on the same leg of the house circuits.

Yep, this is the best way to determine if they're on the same leg. If they are on different legs, you'll see 240V instead of 0V.

 

[Manuka]

Yep, this is the best way to determine if they're on the same leg. If they are on different legs, you'll see 240V instead of 0V.

If you do see 0 Volts, you (or an electrician) can move one of the relative breakers in the panel to the other phase (leg).

 

[Elemental]

Stick your tounge on it.

 

[emartin00]

If you know which breaker each outlet is on, it's easy. Breakers that are directly adjacent to each other (above/below or left/right) are on different legs. Breakers that are diagonal are on the same leg.

 

[electricAnt]

Stick your tounge on it.

Do not try that at home kids.

 

[Fulgerite]

If you know which breaker each outlet is on, it's easy. Breakers that are directly adjacent to each other (above/below or left/right) are on different legs. Breakers that are diagonal are on the same leg.

Depends on the panel design. Not all panels work that way.

 

[electricAnt]

Thanks for the tips everyone.

 

[Loboc]

If you do see 0 Volts, you (or an electrician) can move one of the relative breakers in the panel to the other phase (leg).

Usually, outlets that are that close together are on the same circuit. Also (usually), all circuits in the same room are on the same leg to avoid what you are attempting. For example, if you plug in some audio gear to two different outlets, they BETTER be on the same leg or 240v could hit a 120v device.

 

[Loboc]

Disregarding the wisdom of the ultimate solution..

Lol, my thoughts exactly. This is not a good idea.

Fortunately, the device the OP is talking about has some rudimentary anti-fool built in. Not saying that a sufficiently determined fool can't circumvent these precautions.

 

[Upper5Percent]

Hi all,

Is there a device I can use which will tell me which electrical phase an outlet is operating under?

Of course before I proceed with the below, I'd get an electrician to double check everything and make sure the wiring is safe and sound.

I live in a house rental and there is no 240V outlet and I do not want to scare the landlord with a request for me to pay for the installation of a 240V outlet until we've lived in the house for a few years. I saw there is a product called Quick 220 (http://www.quick220.com) which takes input from two 120V outlets and provides a single 240V outlet. The 120V outlets must be on different phases though. I have two 120V outlets on different 20AMP circuits which happen to be close to each other (5 feet away) so I want to try and use them with the Quick 220.
I've noticed a few leaf and volt owners who are in a similar situation have used this device too.The reason I'm considering this device is that we might add another EV to the household within the next 6 months so our lone 120V outlet might not be quick enough.

If you have to ask...get an electrician from the start...

 

[VoltGuy2014]

Easiest answer, an oscilloscope. However, cheapest, maybe not.

 

[css28]

If he had to ask the question I suspect that he's not a regular oscilloscope user.

 

[electricAnt]

Upper 5 %, I like to learn about new topics thus the main reason I posted to the forum. As stated in my posting, I would consult an electrician ultimately.

If you have to ask...get an electrician from the start...

 

[Upper5Percent]

Upper 5 %, I like to learn about new topics thus the main reason I posted to the forum. As stated in my posting, I would consult an electrician ultimately.

http://www.allaboutcircuits.com/vol_6/chpt_4/1.html

http://www.physics.fsu.edu/courses/Summer12/PHY2054C/lect7-ch22__2.pdf

http://www.ecollege.ie/site/liu/electrical_notes/LL219.doc

 

[Volusiano]

If you got your heart set on the Quick220 and are going to buy it anyway and will come up with a solution no matter what, then you can just get the Quick220 first and try it out. If the 2 circuits are on different legs, you're lucky and the Quick220 will work. If not, then the Quick220 won't work and will tell you via the LED. Now you just have to make it work by:

1. Have the electrician swap one of those circuits to a different leg for you (or DIY if you know how safely).
2. Explore with the Quick220 to find another nearby outlet on a different leg. It may be further and you may need to run an extension cord to reach it, but at least the Quick220 will tell you. If there's none that you can reach, then go back to option 1.

The point is if you're determined to make it work anyway no matter what, just get the Quick220 and use it as your test device. Worst case is you have to do option 1, which is not a terribly big deal.

But DON'T FORGET that those outlets CANNOT be GFI outlets either. You'll need to verify that first and foremost before buying the Quick220. Sometimes they're daisy chained to a GFI outlet somewhere even though they don't have a GFI label and are not obvious because they don't have the GFI buttons right on them. That's why Quick220 includes a GFI detection device with the purchase for you to test it out.

 

[Manuka]

Usually, outlets that are that close together are on the same circuit. Also (usually), all circuits in the same room are on the same leg to avoid what you are attempting. For example, if you plug in some audio gear to two different outlets, they BETTER be on the same leg or 240v could hit a 120v device.

OP indicated he had two outlets on separate circuits....

"I have two 120V outlets on different 20AMP circuits which happen to be close to each other"

 

[Ampster]

Usually, outlets that are that close together are on the same circuit. Also (usually), all circuits in the same room are on the same leg to avoid what you are attempting. For example, if you plug in some audio gear to two different outlets, they BETTER be on the same leg or 240v could hit a 120v device.

How is that possible? (240 hit 120 device) Are you talking about some problem with the audio devices that don't have polarized plugs and could see potential voltage between the phases?