Which phase is my electrik socket on?

Before buying a set of HomePlug powerline ethernet adapters, I'd like to know if the 120 V sockets I plan to use are on the same phase or not. Is
there any easy (and inexpensive) way to figure that out? Those adapters don't really work across different phases. I live in the US.
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wrote:

Find which circuits they're on. If they are on the same side of the breaker box and there is an odd number of breakers between them (not the numbers, but the spaces) they will likely be on the same leg. If they're on the opposite side, count evens. This isn't 100% assured, but it should work. A peek inside will tell you for sure.
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Cameo wrote:

Find out what breaker the receptacles are on and then look at where those are plugged in. They're interleaved with every other breaker down the row being on the same bus. If they're on opposite sides you can usually swap two side by side breakers to get the one you're interested in on the side you want it.
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Not if the breakers go to a 3-wire. The black and red of a 3-wire have to remain on opposite phases or you risk burning up the neutral and starting an electrical fire.
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"Rich." wrote:

Sigh. If you connect the red & black to the same phase for a 240 volt load, it gets zero volts.
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Like the original poster, I was talking about 120 volt circuits and then expanded upon your answer to clarify when a 3-wire is is used as the homerun to the panel. A 240 volt load has nothing to do with it. With a 3-wire homerun, the black and red have to be on opposite phases in order to have the neutral carry the unbalanced load. If the breakers for the black and red were on the same phase, then the neutral could end up carrying the full load of both circuits and burn up. So because of potential 3-wire homeruns, one cannot simply swap breakers that are next to each other without knowing if it can be safely done.
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Rich. wrote:

I hadn't thought of those, I've seen it done once, but I don't particularly care for the idea. Personally I always use standard 2 conductor cable so each 120V circuit gets its own neutral.
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"Rich." wrote:

You didn't state that you were running two 120 volt circuits with a common neutral, so do try moving the goalposts.
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We were talking about outlet circuits, and as you can see above I wrote, "Not if the breakers go to a 3-wire". I specified breakerS and 3-wire. What other conclusion would or could anyone draw from that?
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"Rich." wrote:

An air conditioner, dryer or range with a combination of 120 & 240 volt loads. I can't remember exactly the last time I saw what you are talking about. Probably sometime in the '60s.
Like I said, be specific. This is a world wide group with people using different electrical systems and having different levels of training.
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An A/C, dryer, or any other 240 volt device/appliance would use a single 2-pole breaker, it would not use breakerS. For Christ's sake be man enough to say you mis-read what was written, or your brain wasn't operating at 100% that day, and knock of this trying to justify what you wrote crap. For the record, 3-wire homeruns to a panel to feed two circuits are very much used still today and are not indicative of 1960s wiring.
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"Rich." wrote:

So, you've never seen were some scab used a pair of breakers for a repair to keep up the number of jobs per day, or when 'Mr. Fixit' didn't want to buy a two pole breaker when he already had a spare single pole? Both knew that there would be no inspection of their crappy work, and things would work long enough to get paid, or flip a crappy rehab.
What a sheltered life you must lead. Some of the things I find would cause you to blow out your brains. I was called in to help troubleshoot a home with multiple intermittents a few weeks ago. It had multiple intermittent neutrals, and a piece of 12-2 W/G used to tie the old wiring into the newer part. They ran two 120 V 20A circuits and used the 16 gauge ground wire for neutral, and both supply lines were on the same phase. It was no wonder that 16 gauge wire was burnt. BTW, the two circuits were on separate breakers, and the white wire had no phase tape.
As far as " For the record, 3-wire homeruns to a panel to feed two circuits are very much used still today and are not indicative of 1960s wiring.", I never liked that method and don't remember ever using it. It was considered a cheap trick used by 'fly by night' companies.
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Rich. wrote:

I like them and they certainly have been common in the past. For example I can think of a hospital where substantially all the 120V circuits to patient rooms started as 4-wire 3-phase multiwire branch circuits. Other circuits were also mostly multiwire. But the 2008 NEC requires a "simultaneously disconnect" for multiwire branch circuits. That does not have to be a multipole breaker - it can be single breakers with a (listed) handle tie. It would make multiwires in the hospital impractical.
AFCIs have probably eliminated most multiwire branch circuits in houses since you can't have a common neutral unless the AFCI is 2-pole. You may be able to get a 2-pole AFCI, but they probably cost far more.
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wrote:

The X-10 folks sell a bridge you can put across the phases that will pass the high frequency PLC signals across to the other phase. It is basically just a capacitor but it is in a U/L listed package.
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It just occured to me that X-10 and HomePlug frequencies are quite different and I wonder if that X-10 bridge would even work for HomePlug.
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Cameo wrote:

pull a fuse or switch a breaker and test each outlet, you will then know which ones are on the same circuit.
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wrote:

That doesn't tell you which side of the center tap they're on. The two "hots" are interleaved down each side of the panel, so an odd number between will be on the same "side" of the transformer.
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krw wrote:

Does not matter he just wants the adapter on the same bit of wireing.
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I already know they are NOT on the same fused circuit. I just don't know if they are still on the same phase or not.
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Cameo wrote:

Well when you know what fuse/breaker each is on, then you know which phase each is on just by looking at the panel.
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