AFCI Breaker Tripping Problem

I have a problem where my AFCI breaker (Siemans Type OAF 15amp) trips in my bedroom. It has done this sporadically over the past 3 years
since the house was built. Sometimes it will clear itself up and sometimes it will not. I most recently replaced the AFCI breaker and it is still tripping.
I have nothing plugged into any of the outlets and the ceiling fan/ light switches are off. I reset the breaker and turn on the light switch, the breaker trips. I pull the cord to turn the light off, reset the breaker and turn on the switch, the breaker does not trip. With the light switch off, I then start testing outlets. I plug a power cord (such as an extension cord or one that goes to a computer) into an outlet (knowing there is absolutely zero load on the cord) and the breaker trips.
Where should I now turn to find my suspect. From what i've been able to see of the wiring in the attic above my room, it looks fine...there are no anchor nails piercing the shielding of any of the wires. There have never been any nails placed in the walls since the house was built. Should I check for loose connections on every outlet? Is the suspect in any of the unseen wiring somewhere in the walls? Can I just dump the AFCI and go to a regular breaker?
Thanks all for your help in clearing up this pesky matter.
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I would isolate that circuit, and disconnect anything like the light/fan and hit it with a shot of 250volts of megger voltage between each "pair".. Also go completely through it, and check all the connections including the neutral connection in the panel. It could also be that it's neutral is mixed with the neutral of another circuit, and when that other circuit has a load, it trips your arc fault breaker. One way to test for that is to shut off every other circuit except the one giving you trouble, then see if it still happens. If it goes away, you might start looking for a neutral connection between two circuits that should be isolated. In another scenario, it could be that your wiring was installed on a piece of 3-wire cable, and it will never work right until it is rectified, by either re-wiring it, or, sometimes you can get an arc-fault breaker that will work on a 3-wire circuit. Hard to tell without being there, but these intermittant problems have been neutral leakage and neutral miswires in most of the ones I've worked on.
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On 26 Apr 2007 05:56:51 -0700, slowone snipped-for-privacy@hotmail.com wrote:

Look at the big wirenut full of white wires in the ceiling boxes to be sure there is no copper showing. When you stuff that all back together it is easy to short to ground.,
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A coworker had the exact same problem. It ended up being a staple that had pierced the romex and shorted the neutral to the ground. This caused the GFCI function of the AFCI breaker to trip any time there was load. Lucky for him it was in a section of wire that was the ONLY exposed portion (atic) of the entire circuit.
Charles Perry P.E.
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