...BigB,..what type of wire is present inside the conduit now?? If there is so much as a tiny knick in the wire,and moisture gets in,it sets the stage for a low resistance short.The resulting arc can burn away for awhile,till it becomes a dead short or...clears itself by melting itself through.EMT rusts easily, and because of it's thinwall,can create jagged edges for conductors to be sliced up on.I would probably pull out the entire run,start from scratch,repair/replace any rotted or otherwise damaged pipe,and pull in new lines..but before that,with the circuit on...if the breaker holds,try to catch it on a day after or during a rainstorm,,BUT BE CAREFUL!!take a digital amprobe reading from the panel side, with EVERYTHING on the other end disconnected..including the switch to the defunct post light.if you open up the switch,and remove it,you may find a surprise "feed-out" circuit in the box going who knows where??...If you get a reading of 20 milliamps to 5 amps,with nothing connected,you've got yourself a low impedance short, or a leakage to ground..and that would be objectionable even at 1 amp... Good Luck!!
Russ
PS..I'm far from an authority in this scenario,but I've had my fair share of head-scratcher's and I usually find my culprit..
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...Let us know how you make out,..e-mail me if you want!!
[This message has been edited by Attic Rat (edited 08-13-2004).]
