The longer earth pin ensures that the earth path is connected before the live pins, and that it remains connected until after the live pins are disconnected. The earth pin is too large to be inserted into the line or neutral sockets by mistake.

The British "Type G" plug is widely considered one of the safest electrical designs in the world due to its three-pin configuration: Live, Neutral, and Earth (Ground). The third pin, the Earth pin, is slightly longer than the others. Its primary job is to act as a safety "key." Inside a British socket, the live and neutral holes are covered by protective shutters to prevent children from sticking objects into them. These shutters only open when the longer Earth pin is inserted first. Additionally, the Earth pin provides a safe path for electricity to escape to the ground if there is a fault or short circuit in the appliance, preventing the metal casing from becoming "live" and shocking the user. Furthermore, every British plug contains its own internal fuse (usually 3A, 5A, or 13A), which provides an extra layer of protection against power surges, making the entire system exceptionally resilient compared to the two-pin designs used in many other countries.