[mikehinton]

About 7 years ago, I installed a new wiring system for my shop, barn, and a couple of other outbuildings. All 4 of the circuits are serviced by a sub-panel, which was installed by our electrician. I did all of the other wiring myself (I've done similar projects several times over the last 20+ years). The circuits are all very simple - just a bunch of outlets with a few switched outlets for fluorescent lighting. There are no 3-way switches anywhere.

Everything worked fine upon installation, and continued to work fine until a couple of weeks ago. I went out to the barn to plug in a battery charger, and no power. Went to the box and found that the circuit breaker had tripped. That seemed odd, but I just reset it and continued on. A couple of days later, I went to turn on overhead lights, and same circuit was tripped. Strange. Reset it and continued. Last week, I encountered the same thing. This time, when I reset the circuit, I heard a "pop" coming from the barn, and the breaker tripped again. As far as I can tell, there was no load on the circuit when the breaker tripped.

So, I'm figuring that there must be a short somewhere in that circuit. A couple of questions: 1. Why would a short suddenly manifest itself after 7+ years? 2. Is there a way to track down the source without disconnecting everything? The "pop" I heard was coming from a junction box in the barn. When I removed the cover, the large wire nut (joining 6 neutral wires) was burnt to a crisp.

Any advice appreciated! Thanks for reading!

Mike