That ground wire is incredibly important because it provides a safe “exit” route for any extra voltage that the outlet might receive.You see, most residential outlets are designed to handle up to 120 volts of electricity.Before the 1960’s, wiring run through our homes (also referred to as circuits), had two wires, a hot and neutral, usually wrapped in cloth sheathing.
I bought a receptacle tester and tested the newer style outlets, which all tested as correct wiring.(2) A receptacle protected by a listed outlet branch circuit type arc-fault circuit interrupter type receptacle.(3) A receptacle protected by a listed combination type arc-fault circuit interrupter type circuit breaker. Listed tamper-resistant receptacles shall be provided where replacements are made at receptacle outlets that are required to be tamper-resistant elsewhere in this Code.In fact, in 1962 the NEC (National Electric Code) began requiring that all new houses be built with 3-prong outlets (instead of 2-prong) because they protect against: Two-prong outlets are unsafe because they’re “ungrounded”.An ungrounded outlet is one that doesn’t provide a safe route for stray electricity to be diverted into the ground.