How often should ground-fault circuit interrupters be tested? How?
Give them a test. Test ground-fault circuit interrupters (GFCIs) monthly. Turn on a night light plugged into the outlet. Press the test button. If the light turns off, the outlet is working properly. If the reset button pops out but the light stays on, the GFCI isn’t working. Press the reset button to return the outlet to normal. In addition, contact a qualified, licensed electrician to determine whether your GFCI needs replacing.