A recent survey by the Electrical Safety Foundation International found that about one-quarter of Americans don’t understand how ground fault circuit interrupters (GFCIs) work. Here’s some information about these vital devices:

• GFCIs monitor the electricity flowing in and out of a product. If the electric current fluctuates, the GFCI shuts off the power to prevent shock.
• You’ll find most GFCIs where electricity and water could mix, such as in kitchens and bathrooms.
• Test your GFCIs once a month. Plug in a nightlight and turn it on. Push the “Test” button; the light should go off. Push the “Reset” button to turn the light on.