3 Things to Know About the Third Prong on a Plug

The third prong is a ground wire that prevents electric shock. If a hot wire inside a device touches the metal casing, the ground gives electricity a safe path back to the breaker panel instead of through your body.

Do not use a two-prong adapter to bypass the ground. Removing the ground breaks that safe path. The adapter’s metal tab only works if the outlet box is grounded, which most old two-prong outlets are not.

In a house with two-prong outlets, replace them with a GFCI or use a grounded extension cord. Label the GFCI “No Equipment Ground.” Do not assume the adapter is safe.