What are ungrounded electrical outlets?
Ungrounded electrical outlets (two-prong receptacles) are usually found in older homes that have the original 2-wire ungrounded system. This system was designed with only the hot (black) and neutral (white) wires. In modern construction, a properly grounded circuit requires the use of a 3-wire system that contains a ground wire in addition to the hot and neutral wires and a three-prong outlet. If the ground wire becomes disconnected, a grounded outlet becomes ungrounded.
Why can ungrounded electrical outlets be dangerous?
Ungrounded electrical outlets are common in many homes built before the early 1960’s. It’s the way homes were built back then. Unfortunately, they pose a safety hazard. An ungrounded electrical outlet doesn’t have a ground wire. This means there’s no path for the electricity to flow into the ground (earth) if there’s a fault. A fault is when something shorts out, and a short can inflict serious injury or death, cause overheating, and spark a fire.
In the 70’s, most new electrical appliances, vacuum cleaners, and such started coming with 3-prong plugs. I remember it was frustrating because you always had to find an adapter, commonly known as a “cheater,” so you could plug the new appliance into the 2-prong outlet. The most common, but incorrect “fix” was to replace the old 2-prong outlets with 3-prong outlets. Problem fixed, right? No way! This is dangerous because if you see a 3-prong outlet, you assume it’s properly grounded, and in this case, it’s not. You still don’t have a ground wire.
What is a GFCI, and how can it help?
The requirement for grounded outlets was introduced in 1962 by the National Electrical Code (NEC, 210-7), and the replacement of ungrounded outlets with grounded outlets was addressed in 1965. In 1984, the NEC amended 210-7 to allow the use of a ground fault circuit interrupter (GFCI) to provide protection for a non-grounded circuit. A GFCI is a device that’s designed to protect people from electrical shocks by monitoring the current flowing through a circuit. If an abnormal imbalance is detected, the GFCI will sense it and trip (open the circuit), instantly de-energizing the circuit. This prevents electrical shocks by interrupting the flow of electricity before it becomes dangerous.
GFCI Outlet
It’s important to know that on a 2-wire ungrounded system, a GFCI outlet needs to be installed at every outlet to provide proper protection. In this case, every outlet must be labeled “No Equipment Ground.” On a 3-wire system, the GFCI only needs to be installed on the first outlet of the circuit.
These explanations are very basic, and there are many considerations regarding electrical codes and the myriad of updates they’ve undergone throughout the years. If you ever have any questions or concerns about the safety of your electrical system, it’s always best to consult with a qualified electrician.
Conclusion
First and foremost, it's important to understand what an ungrounded electrical outlet is and why they can pose a serious safety hazard. An ungrounded electrical outlet is one that does not have a ground wire connected to it. This means there’s no path for the electricity to flow into the ground if there’s a problem with the outlet or the wiring, which can lead to electrical shocks or cause a fire.
At HomePro Inspections, we’re trained to identify potential concerns and are always looking for these types of issues when inspecting a home. When found, issues are documented and recommended for resolution by a qualified professional.
Visit our website to learn more or to schedule your home inspection in the Rochester, Owatonna, and Faribault, MN areas. You can contact us today at (507) 202-8942 or use our online “Schedule Now” feature to set up an appointment.