Recently, the lone receptacle (a GFCI) in my bathroom started making a buzzing noise when something was plugged into it, then tripped. I turned off the power from the panel and pulled out the receptacle. I attached a photo. There is a 14/2 and a 14/3 that enter the electrical box. The black wire from the 14/2 and the red wire from the 14/3 are connected with a wire nut. The Black wire from the 14/3 is connected to the line side, as are both neutral wires. Two questions: Was this wired correctly? (The receptacle had been working properly for 10 years). I assume there was some type of short circuit that made the neutral side to get burnt up like that (the hot side was OK). I see some bare spots on the neutral wires, but I'm not sure if those bare spots caused the short, or if the short melted the wire to create the bare spots. I can replace the receptacle easily enough (making sure to trim off the bare spots on the neutrals), but I want to make sure that I don't run in to the same problem again. Any thoughts?