Loss of power to several circuits at the same time without tripping the breaker

Sounds like you have a problem in your panel. How old is it? Sounds like it could be a split-buss panel and only the "lighting main" fed breaker are being affected.

In my strong opinion you need to have a qualified/real electrician (ie: NOT a "handyman") come out and check it. This is typically NOT a DIY fix.

You sound like you have a good handle on testing. I like that you have traced the problem to the panel. If the breaker is putting out 24V at times and 120V at other times than there is a problem somewhere around there.

You have two legs in your panel (red wire and black wire). You have tested all the breakers in your panel and it seems like you are getting 24V on some and 120V on others. I understand you say that all the problem circuits are on the same leg. Are there other loads on that leg that are testing 120V and not 24V when the others are. It would be good to know if it is just those breakers or that entire leg that is having problems. If you need help on testing the legs (hot to ground) than let me know.

Otherwise if you are not having the issue right now and therefore cannot test that than I would take out a few of the breakers that seem to be trouble and switch them for a known good breaker. It could possibly be some bad breakers.

Are all the breakers close together? If they are it sounds like some heat might be causing problems, making the breaker not operate as usual. If this was a Federal/Pioneer panel I wouldn't be surprised if it was a bad breaker. They have a bad name for not tripping when they are supposed to. And maybe a breaker that will not trip is heating other breakers up.

I would also check the bus below the breakers. Does the bus that the breakers sit on look okay. I can't imagine there would be a problem there but it would be good to look at it just incase something happened that I cannot think about.

Remember to turn the breakers on first on any breaker you remove from the panel. Testing to make sure OV is on the breaker to ground when the breaker is off sounds like a good plan with these dodgy breakers. They might be hard to get out to. Wear safety glasses and turn off anything that will make you feel safer getting them out if they are "fused" on there from too much heat. Perhaps turning off the main breaker would be a good idea!

I can't see the power meter being the problem unless an entire leg is seeing 24V. Otherwise I am thinking breaker problems. But try to investigate if there is a reason they stopped working besides perhaps maybe ,like I said earlier, a breaker getting too hot because it's not working properly. Just do visual inspections.

I'd (very carefully) do the voltage measurement on the supply-side of the breaker both in normal, and abnormal, states.

Do this with the main breaker off - so your house wiring can't be affecting your measurement.

You are likely getting the odd-voltage-readings (the 24VAC) because your 240V appliances are back-feeding power from the "good" side to the bad side when the problem occurs.

If, with the breaker-off, you measure low voltage on one of the supply side "phases", then you should call your utility and start talking with them about it.

One other possibility that I encountered once: the two wires carrying the two phases from the power pole to the two legs each had an inline fuse (about the size and shape of a thumb) outside the house, where the lines entered the service pipe. One of the fuses was going wonky, and causing lights to flicker on any circuit on that leg...

The fuses were sheltered by the overhang of the soffit, but they were somewhat exposed to snow/rain/moisture. When the utility came to check out my problem, the fuse was swollen and steaming slightly in the cool air. An easy diagnosis ...

I’ve had this experience, and the neutral at the main, had a corroded lug, and for some reason it would be in and out, but that was the culprit! The solution, a new meter base!

Picture is probably best to see make/mod/type to the panel & ckt otherwise we are sticking to guessing. My experience with my last similar problem=light flickering which eventually lead to power loss; problem found after tedious pain taking effort of localizing insulation stripped during the initial install/build. The outer jacket of the ROMEX cut and stripped from the base of the conduit to the panel inner side to the respective cb which has a 2 feet cut that at first glance it would be hard to see the bare copper if I didn't remove the black wire out of its cb tie then I would never see the damage. Problem fixed with a piece of 28 inch long heat shrink over the black wire = no more light flickering, case closed. Good luck!

I’m not an electrician, but I had a somewhat similar electrical problem with the fluorescent tube light fixture not working in our closet With switch on I measured low voltage. I replaced the ballast and it works fine. Could be you have some florescent lights on that circuit that has a bad ballast causing low voltage but not tripping breakers.

I ended up here on this thread due to similar symptoms - occasional flicker of lights , not tied to load demands from within the house or windy weather outside. Yesterday morning woke up to the power off in the whole house, except one or two circuits (!) The hallway lights worked, and one plug in the kitchen (for the coffee maker thank god). I went to the panel and no breakers were tripped. I called the power company , they came and immediately noticed the connectors at the top of my mast were weathered and ‘burned back’ , so they changed two of the three. They also swapped my meter on a just to eliminate another possible culprit. When power was re-applied, still no lights in the house. One of the crew came in and cycled the main breaker and there was a spark as it connected, and the power did come on. He said “that’s the problem right there” (the main breakers at the top of my panel) My electrician friend came over and ,with the meter off outside, pulled the main breakers off and cleaned the contacts with very fine sandpaper and some deoxidizer gunk that went right on the contacts of the breaker. That helped but didn’t fix the breaker. It was showing signed of oxidaztion and arcing. This panel has push-on breakers. It’s a siemens with two 125amp mains. Not sure if that is uncommon or not but the way he said it makes me think maybe. (New in 2000)

Anyhow new main breaker getting installed today. Just posting this for the next guy. (Any further news I’ll let you know)

Cheers.