Weird Power Outage in Certain Rooms- Condominium
Phase/Leg Out
You have lost one phase or leg (terms vary) of your power. 120/240 power comes in on 3 wires - two hots each 120V from the neutral and 240V from each other. Most breaker panels are designed with alternating legs. Left &amp; right in each row are on the same leg. 240V (dryer, oven, A/C, etc.) use a pair of breakers, one on each leg.
Your electrician should have been able to figure this out. In any case, CALL YOUR ELECTRIC UTILITY and tell them you have an intermittent phase/leg out. They'll check it out for free and fix it if it is on their side, which is very often the case.