Is it true that flourescent light bulbs get hot enough to trip heat sensors in mew electrical construction ?

They should not get hot enough to trip the thermal protector if that is what you are referring to. There might be a couple of issues. If the are incandescent cans, are you using the standard flourescent bulbs or the ones designed for recessed cans? If they are the standard compact flourescents' then are they going out or is the thermal protector tripping? Most standard compacts would probably hold up in a recessed can but if they are cheap ones then the internal ballast might not like the base up operation. That is one possibility. The other issues are. Did the contractor provide the cans? If he did might they be Halo brands? Cheapest ones made with frequent consumer complaints. The other issue is whether they were IC rated. If not then insulation making contact with the housing could be a factor, and a dangerous one at that. Try switching out the flourescent ones for standard incandescent bulbs and see if the problem persists. Make sure you don't exceed the wattage rating for the cans you have. Also very unsafe. If none of these things help then there might be a wireing issue or overload issue.