Elliott Sound Products Dangers of Re-Stringing a Guitar Near a Power Outlet 

Special Warning to all Guitarists

When replacing guitar strings, never do so anywhere near an amplifier (especially a valve amp), nor close to a mains outlet. Because the strings are thin - the top "E" string in particular - they can easily work their way into mains outlets, ventilation slots and all manner of tiny crevices. The springiness of the strings means that they are not easily controlled until firmly attached at both ends. This is very real - the image below is an actual photo of an Australian mains plug that was shorted out by a guitar string. Luckily for the guitarist, both active and neutral were shorted together, blowing the house fuse. Had the string only contacted the active, the guitar and guitarist would both be live. Touching any earthed metal could easily have resulted in a fatal electric shock.

This is a real photo, taken of a mains plug that had a guitar string across the active and neutral pins. Needless to say, the plug had to be replaced, and it must have made an almighty flash when it happened.

        (Photo courtesy of Phil Allison)