any ideas on what would cause flickering on 2 circuits and buzzing on the breaker of a third circuit? I can hear a slight arcing noise at the breakers when the lights flicker. The buzzing on the third breaker stops when I shut the lights on that circuit. The flickering circuits are on one bus and the buzzing circuit is on the other bus. I tightened/checked almost everything in the panel and swapped breakers around, no change. I called the power company and they're going to check the supply line outside. It has been raining the past few days and I also have a transformer on the pole outside my house. I'll be calling an electrician if they don't find something definitive. Keeping the main off in the meantime. Thanks in advance.
Breaker types are not interchangeable, even though they "fit"
The problem is you have brand A panel and brand B breakers. That is not legal because it is not safe. At this point you have probably wrecked the busbars on the otherwise quality Murray/Siemens panel.
They may "snap in", but they don't snap in with the correct amount of clamping force or with the correct mating on the bus bars - and so they arc. If they had been arc-fault breakers, they would have tripped.
- Look at the labels in the panel for which breaker series are actually allowed in that panel.
- Inspect every breaker in the panel.
- If it is not a Murray/Siemens breaker of one of those series, throw it in the trash.
- Then, closely inspect the bus bar (warning: it's hot) and if the bus bar is chewed up by arcing damage, stop using that breaker spot and fill the hole with a blank cover.
- Get proper Murray/Siemens breakers of one of the series actually specified by the labeling on the panel.
Very rarely, Brand X will make breakers specifically for Brand Y panels, but that's too rare to bother with and it won't save you any money.