Here’s a little theoretical knowledge to help you figure out what you are looking at.
Most homes (in the U.S. at least) are fed from a center tapped transformer. The center tap is grounded, which gives you two “hot” lines. The voltage between either hot line and the neutral is 120 volts, and the voltage from one hot line to the other is 240 volts. The center tap (neutral) is physically connected to earth ground (literally, by either the water pipes in an old house or by a copper rod in a newer house) somewhere close to the breaker box.
The three wires (line 1, line 2, and neutral) all come into your breaker box. The neutral line goes directly to a bus bar in there, and the two lines (aka phases) go through the main breakers.
From the breaker box, the wires all go out through your house. Most breaker boxes are set up so that the slots alternate between phase 1 and phase 2, as Kevbo said. If you want a 120 volt wire, you install one breaker in the slot. If you need a 240 volt wire, you insert a breaker that takes up two slots, so that it gets one wire from phase 1 and the other wire from phase 2.
Here’s a diagram in case it still isn’t clear:
If the electrician who wired up your house did his job properly, half of your outlets will be on phase 1 and half of them will be on phase 2, and all of your 240 volt appliances will be connected to both phase 1 and phase 2. On the other hand, if you’re the idiot who wired up my house, you end up with all of the outlets around the outside of the house on one phase and almost nothing on the other. :rolleyes: Anyway, grumbling aside, the point is that many houses aren’t wired up with the outlets split exactly evenly like they should be.
From each breaker, the wires go out to branch circuits. Each circuit will go from one outlet to another to another (or to light switches and that sort of thing). Sometimes you will have junction boxes which split the branch into two paths.
As to which breaker goes where, this is all supposed to be labeled neatly and properly on the breaker box. However, I have never, ever, lived in a house where the labels were correct. I’m sure there are some out there somewhere, but most of the ones I’ve encountered have either been blank or wrong. People switch out fuses for breakers or make major wiring changes and no one ever bothers to update the list. So, never assume that the list is right, because usually it isn’t.
Now, back to your problem. If you are losing a bunch of outlets, either they are all on the same branch and you just lost that branch, or you’ve lost one of your phases coming in. Since the electric company just made a change at the meter, that makes a phase problem more likely.
Take your handy dandy DMM and measure the voltage between phase 1 to neutral and phase 2 to neutral. If you aren’t comfortable poking around in your fuse box, you can measure this at your dryer or oven. You aren’t looking for the exact number here, because the voltage to your house can vary. Power companies used to guarantee +/- 10 percent, but these days a lot of them guarantee +/- 5 percent, so if you are off by that much it is perfectly fine (generally speaking, the farther you are from the nearest substation the lower your voltage will be). What you are looking for here is a difference in voltage between the two phases. If phase 1 is 119 volts and phase 2 is only 115 volts, that means you’ve got a connection problem with phase 2. (very likely, given your symptoms).
If the phases are identical in voltage, you can repeat the test with the problem outlets, and see if they have a reduced voltage even while they seem to be operating properly. That also would indicate a bad connection someplace.
As for what the specific problem is, it could be a bad or loose connection at the transformer or meter, it could be a bad connection inside the breaker box itself, or it could be a bad connection on the branch circuit, if all of these outlets are on the same branch. The bad connection could be on either the hot side (the black wires) or the neutral side (the white wires). By the way, the third wire (green) is a protective ground, and doesn’t carry current under normal circumstances, so it can’t be the problem here.
Another problem you could have is a corroded earth ground connection. This is dangerous, because it can make one phase go down while the other goes up by the same amount. In other words, you could end up with 40 volts on phase 1 and 200 volts on phase 2 (but still 240 volts between phase 1 and 2) if the ground connection is bad. This could damage everything on the phase that ends up with the higher voltage, and as a result it can easily result in a fire in your house.
Feel free to poke around with your meter, but intermittent connections also tend to be hot connections due to more current being forced through a smaller area of connection. This is what causes house fires. Get this fixed ASAP.
