If your home was built between 1920 and 1961, you may be familiar with the inconvenience of two prong outlets. These outdated devices only have two wires running through them: a hot wire and a neutral wire. Two-prong outlets lack a third grounding wire, which can leave you unprotected from stray currents and result in electrocution or a power surge through sensitive electronics, often destroying them in the process.
Why is a Ground Wire Important?
In homes built since 1962, U.S. electrical code has required all outlets be constructed with a ground wire. This ground wire protects electronics and people from electrical surges and faults by providing a pathway for extra energy to escape the house's circuitry. When a fault or surge occurs in a modern home, the excess electricity travels through the ground wire to the electrical panel. There, it will trip the circuit breaker or blow a fuse, thereby shutting down the circuit before damage occurs. The energy then continues through the ground wire into the earth below the structure, where it dissipates harmlessly.
Without grounding, it’s impossible to protect your electronics and appliances from harmful power surges. Modern sensitive electronics come with three prongs for a reason. Anywhere you plug in computers, TVs, air conditioners, vacuum cleaners, and other devices, three-prong outlets are essential. Just plugging devices into a surge protector with a two-to-three prong adapter offers no protection at all. Surge protectors work only if they are connected to a ground wire– lacking this, they offer no better protection for your electronics than do standard outlets.
Is it Even Legal to Have Two-Prong Outlets?
For almost 60 years, code has required all new construction have grounded, three-prong outlets. In older homes, however, the National Electrical Code (NEC) allows you to replace an existing two-prong outlet with another one like it when no ground wire is present in the circuit. This means if you must replace a faulty two-prong receptacle, you aren’t breaking any codes if you choose not to upgrade.
Four Ways to Upgrade Two-Prong Outlets
Replace with another two-prong outlet
If your existing outlet is faulty, the NEC allows you to replace it with a new outlet just like it. Two-to-three prong adapters allow you to physically plug in a device that requires a grounded plug, however, this is the riskiest solution as it offers no protection from shock or damage to electronics. Surge protectors plugged into these "cheater" adapters cannot do their job without a ground.
Replace with a GFCI outlet
A better solution is to upgrade your outlet to a ground fault circuit interrupter, or GFCI. According to the National Electrical Code, you must label the outlet as “GFCI protected” and “no equipment ground.” A GFCI installed in this way is not grounded, so while this option prevents shock-related risks associated with two prong outlets, it still provides no ground protection for sensitive electronics.
Retrofit a modern outlet if your metal box is already grounded
Many two-prong outlets were installed in metal boxes, and while the circuitry itself wasn’t grounded, the individual boxes sometimes were. If your house has two-prong outlets with metal boxes, it may be possible for you to ground your outlets without rewiring your home.
To find out whether the metal housing is grounded, purchase a circuit tester. Insert one of the tester’s prongs into the hot slot (the shorter slot in the outlet). Place the other prong onto the center screw holding the cover plate. If the tester lights up, it means the metal box is grounded. You can take advantage of this grounded housing and safely install a three-prong outlet by attaching it to the armored, or BX, cable in the back of the box.
Rewire the circuit to add grounding
If a circuit test reveals that the box is not grounded, hire a trusted electrician to rewire the circuit with a three-wire cable to provide the necessary ground. This solution requires the most work and can be expensive depending on the size and construction of your home. However, it is the best way to ensure your family and electronics are protected from stray currents that can cause electrocution and power surges.
For help upgrading your two prong outlets for safety and electrical code compliance, please give Bell Electric a call at 540-552-5397