Ground fault protection, aka GFI (Ground Fault Interrupter) devices sense a small flow of electric current to ‘ground’ and respond by immediately shutting off the current. Hopefully, this prevents the human body from becoming a path to ground and prevents severe electric shocks and death by electrocution when insulation failures of any type occur. They are usually incorporated in circuit breakers and electrical outlets but “plug-in” GFI units are available.