I have seen 12-2-2 used only on one job. It was used as a home run for the Bathroom with a GFI breaker for the receptacle and the other 12/2 for the light.
Don't know about the cost but, it made a neat appearence in the two gang box. Switch and recept.
Alan--
Are the Smoke detectors on the AFCI circuit ? If not, that may be the reason for the seperation.
[This message has been edited by Alan Nadon (edited 01-16-2007).]
