Hey, does anyone know how to tell which electrical outlets are on the same circuit? Is there some kind of tool out there you can buy that you can plug in one outlet then go around to each other outlet and when it sees that other plug it will light up or something? When my house was built the electricians did a SHIT job, but since I switched from central AC to window AC I have some power to play with but want to make sure what outlets are on what breaker. I know they messed up because a couple outlets in my living room go out at the same time ones go out in my office. And that's two room away. Unless that's the way it is done? I was NEVER any good at electricity. Horrible at it.
One way to tell is to open up the load center panel and look at the bars below the circuit breakers.
The breakers are often every other breaker on same leg/phase.
That is why dual leg 240 curcuit breaker is wider, it needs to grab 2 different phase.
If you have a voltmeter _AND_ skills to measure voltage at the outlet _AND_ a long extension cord.
measure between the hot legs of different outlets.
(The hot leg is the small plug prong)
0 volts equal same leg/phase
240 volts equal different phase
DO NOT TRY THIS IF UNCOMFORTABLE WITH AC WIRING
You usually only get one time to burn your house down.
I'd suggest saving that one time for when you need to destroy evidence or something similarly nefarious.
YMMV
EDIT
What I described above is how to tell if circuits are on different legs.
The tool Joe mentioned is the EASIEST way to locate outlets on the SAME circuit.
You could get a lamp, turn off all but one circuit and test every outlet for live outlets, rinse, repeat.