Having strings that are not properly grounded on your archtop guitar can produce static and humming noises that will lessen the sound quality. There also is a risk of electrocution and equipment damage if an electric spike travels back from your amplifier into your guitar. While the vast majority of electric guitars come from the factory with proper grounding, it is possible for the grounding to break free. If you begin to hear humming when you are not touching the strings or feel a slight electric buzz in the strings, it is time to reground your strings.
Unplug the guitar from the amplifier. As you will be working with potential live wires, make sure that the guitar is completely free from any source of electricity. This includes any effects or pedals that you may be using.
Loosen all the strings. Do not remove the strings as they need to be on the guitar to properly check for the ground.
Inspect the bridge unit. The bridge on a archtop guitar is attached to the body of the guitar and is positioned after the electronic pickups. All the strings travel over the bridge before being connected to the tail piece of an archtop guitar. Look closely at the bridge and locate a small wire that connects the top of the bridge to either the side, front or back of the bridge itself. This wire should be soldered to a metal part of the bridge.
Solder the bridge wire. If the bridge wire is either not properly connected to the bridge or is loose, clean off all of the old solder and use a small amount of solder to reground the wire to a metal part of the bridge. It is important that you make a clean connection by removing all the old solder, dirt and grime away from the metal grounding area.
Let the solder cool and harden. Re-tune the strings and connect to your amplifier. If you properly grounded the bridge, there should be no humming sound left.
If after grounding your strings you still experience humming, you probably have a short or a missing ground in either the pickups or volume/tone controls.