The Ground Fault Return Path

Why a length of copper wire — not the ground rod outside your house — is the thing that actually keeps you from getting shocked.

Ask most people what protects them from a faulty appliance and they'll point to the ground rod driven into the earth at the electrical service. It's a reasonable guess — and it's wrong. The ground rod barely participates in clearing a fault at all. The part doing the real work is a dedicated copper conductor that runs alongside every circuit, whose entire job is to give fault current a path so much easier than a person's body that current has no practical reason to go any other way.