3 Things to Know About GFCI Protection and Extension Cords
The GFCI outlet protects the cord If the extension cord is plugged into a GFCI-protected outlet, the cord itself does not need an additional GFCI. The outlet handles that.
GFCI does not fix a damaged cord A frayed or indoor-only cord used outdoors is still dangerous, even with GFCI protection. GFCI prevents shock but does not stop a fire from a damaged cord.
Check the cord’s condition and rating Make sure the cord is in good shape and suited for the environment. GFCI protects you at the source, not from a broken extension cord.