Which appliance in residential settings does not need to be connected to an equipment grounding conductor?

In residential settings, appliances that have a three-prong plug usually need to be connected to an equipment grounding conductor as a safety measure to prevent electric shock. However, certain appliances can operate safely without a direct connection to an equipment grounding conductor if they are double-insulated.

A toaster is often designed with an insulated housing that provides sufficient protection against electrical shock, making it unnecessary to be grounded. This design allows it to be safely used without the grounding connection, as the double insulation protects the user from electrical currents.

In contrast, appliances like microwaves, refrigerators, and washing machines typically have metal casings and other components that can present an electrical hazard if not properly grounded. Grounding these appliances helps to direct any stray electrical current safely to the ground, reducing the risk of electric shock and ensuring safety in the home.