Occupants of older homes may sometimes notice that their house is not fully compatible with some forms of newer technology. For example, an adapter might be needed in order for the power cord of an appliance to fit into an electrical wall socket. Owners of homes that require the use of an electrical plug adapter most likely need to upgrade their electrical wall outlets.
You may have noticed that some of your electrical wall sockets are designed to accept only power cords with two metal prongs. However, the power cord connector on many appliances contains three prongs. Although an appliance can usually operate normally with the use of a plug adapter, a crucial element of safety may be lost in the process.
Basic 2-wire fault detection
Electrical outlets with 2-prong receptacles were routinely used in home construction decades ago. The wiring to the outlet provides electrical current to an appliance in use. The wiring also returns the electrical flow back to the central power panel containing the circuit breakers. If an electrical fault occurs in an appliance motor, the 2-wire system is likely to correctly trip a circuit breaker.
Enhanced 3-wire fault detection
A third wire is needed to provide protection from electrical faults that are not in the motor of an appliance. The metal frame of a washing machine, for instance, could become energized if the metal were to come in contact with a frayed electrical wire. Screws or bolts inside an appliance could loosen, possibly bridging the gap between the frame and the electrical wiring.
The purpose of the third wire is to detect electrical faults that lie outside of the primary electrical circuit. If an appliance is not in use, the random loss of incoming electrical current might not be sufficient enough to trip a circuit breaker. As a result, the energized metal frame of an appliance could present a serious safety hazard.
Installation of 3-wire power outlets
In addition to wall sockets, an additional grounding connection can provide a greater degree of safety to light fixtures and ceiling fans. If your house has electrical outlets with 2-prong receptacles, it likely indicates that some additional wiring is also needed to deliver the added protection.
Electrical wiring for new residential construction typically contains all three wires bundled into a single cable. Depending on your local building code, a licensed electrician can determine the best option for running the wiring needed for 3-wire connections. Contact an electrician for more information about electrical repairs.