USB Ports and Guitar Strings Give Me an Electric Shock—What Should I Check?

Normal power-supply leakage can sometimes cause a faint tingle when grounding is missing, and that sensation can travel through USB equipment and guitar strings. Even so, a noticeable shock shouldn’t be ignored. Disconnect the setup, avoid using the guitar with it, and get both the household grounding and the PSU checked before reconnecting everything.

The symptoms are consistent with the PC chassis and connected equipment not being properly grounded, so your body is providing a path to ground. Try a known-good, properly grounded wall outlet—not just another socket on the same circuit—and test the original outlet with an inexpensive receptacle tester. If the outlet passes, have the PC’s power supply and cable inspected.

First determine whether this is a single static zap or a continuous tingling sensation. A one-time snap is usually static discharge, but repeated or continuous current points to leakage from an ungrounded or faulty system. If it continues, don’t keep testing it with your body; use an outlet tester and have a qualified electrician check the receptacle.

Unplug the computer immediately and stop using it until the problem is checked. A continuous or strong shock can indicate a faulty power supply, wiring problem, or missing protective earth. Don’t try to improvise a ground wire—have the outlet and PC inspected, and consider replacing the power supply if it’s suspected.