I'm stumped! About 2 weeks ago our breaker box was flooded in our basement from a pipe. As a repercussion one circuit from our panel lost electricity. We replaced all the flooded breakers in the box just to be safe. Well, that circuit keeps losing electricity. It never trips the breaker. Looking at it closer we noticed that the smaller 20 amps are fed to two larger 60 amp breakers. The breakers zig zag back and forth on the panel where they are then connected. It now seems the whole connection is being lost (all of those circuits) therefore the downstairs lights and outlets but not upstairs. As mentioned, the breakers never trip, happens different times of day or night whether in use or not, different lengths of time, and randomly comes back on. What could possibly be going on?

Its not one continuous wire that goes to everything in that circuit... rather more like that goes to the first outlet or switch on the leg... the next segment attached to that switch or breaks and so one. If water got high enough to flood your breaker panel... you likely had those get wet too and got some corrosion and have a connection that's no longer electrically sound. I'd go through everything one by one to make sure.

I strongly advise you to replace your circuit breaker panel. The panel is subject to degradation from water as well as the circuit breakers.
Why take a chance with this?
Replace the panel with a licensed electrician and let him troubleshoot the why...

H.

The breakers zig zag back and forth... They are designed that way. If they didn't do that you would have a hard time getting 240VAC since the 2 circuits have to be on separate feeds. I would be very cautious of DIY in this case.
smaller 20 amps are fed to two larger 60 amp breakers
Unless you are talking about a subpanel, the 60 Amp breakers are not feeding the 20's unless someone failed wiring 101.

If this is an older split bus panel, then it is possible that the 60 amp breakers are feeding the lower half of the panelboard.

Would you be kind enough to supply a picture of the panelboard in question.

Also, as stated above, if this panelboard was damaged by a burst pipe it would be very prudent of you to have the panel replaced by a licensed electrican.

Ran into a house down in the Keys, Receptacle Boxes were about 16" above the floor, Water somehow flooded one box, and filled about 8 1900 boxes(elec boxes), and with the electricity and time the metal conduit running through the concrete walls, closed in on the wire and formed an inpenetrable conduit, can't even pull out 2 conductors out of conduit. You may want to verify no water is sitting in conduits. Good Luck