I have a person that wants to wire in four light boxes and four ceiling fans with switches and I need to know if I can run all four of them safely from one breaker and if so what kind of breaker? This question may be absurd but I just don't know the answer to it. I do home improvement work for a living at least I have the good sense ask a question before I even attempt something I don't know about. needless to say I have not done a lot of extensive wiring. I have put up plenty of ceiling fans and even ran one circuit very short distance in a garage from a breaker panel and I knew to have the proper testing equipment and to take my time and to ask questions if necessary and also most importantly to have the proper tools and some basic knowledge of how to use them. Also, do I have to run the wire through conduit in the attic?
There should be no problem running 4 ceiling fans on a single 15 ampere circuit, though it will depend on what else is on the circuit.
Say a 52" fan is 90-100 watts (at high speed), plus three 60 watt bulbs. That puts each fixture at 280 watts or so. Which means four of them, would be 1120 watts.
A 120 volt 15 ampere circuit, can supply 1880 watts (120 volts x 15 amperes = 1880 watts). Some folks will argue that you should only load the circuit to 80%, so that would be 1440 watts for a 120 volt 15 ampere circuit. Which even so, is still enough to supply the fixtures.
Note: the values used in the answer are an estimate, for example purposes only. Check the listed wattage for the devices you'll actually be using.