For as long as you’ve been living and working in buildings with electrical service, you’ve been plugging things in.
Have you ever noticed how some outlets have just two vertical slots, while others have a third “hole” that makes the outlet look like a strange face? You may have also noticed how many appliances have either a two-prong plug or a three-prong plug.
What is that third hole? Is it necessary? Is it safe to plug something into an outlet with just two holes? Or does it even matter?
Those two-prong outlets are what we in the electrical industry call non-grounded outlets (or ungrounded outlets). Three-prong outlets, by contrast, are referred to as grounded outlets.
Today we’ll show you what all this means, including the difference between grounded and ungrounded outlets, and how to address the outlet safety concerns that come with using older two-prong electrical outlets.
What Is a Grounded Electrical Outlet?
All outlets have a hot wire that delivers electricity from your local power source to your home, and a neutral wire that sends electricity back to the power source. If an outlet has only these two wires, but has no ground wire, it is a non-grounded, or ungrounded, outlet.
If the outlet has a third wire called a ground wire, it is a grounded receptacle, or outlet, and will have the familiar three slots. A ground wire is an important safety feature. If your home’s electrical system, or an individual outlet, get a surge of excess electricity, this can raise the risk of fire, shock, or electrocution.
This power surge, also called an electrical fault, travels from the grounded electrical outlet back to your home’s main electrical panel, out through the ground wire to the earth, which absorbs the excess energy. By directing the power surge to the earth, the ground wire reduces the risk of damage to your appliances and injury to you and your family.
The differences between grounded and ungrounded are quite simple. When it comes to appearance, ungrounded outlets contain two prongs or holes while grounded outlets contain three.
Electrical devices that can be plugged into an ungrounded outlet include small kitchen appliances, lamps, and radios. Grounded outlets can more safely provide power to larger devices including computers and televisions. The third wire in these three-prong outlets is known as a grounding wire and allows for an additional path for electrical currents. These outlets are less likely to cause short circuits compared to ungrounded outlets. Grounded outlets are for improving safety and preventing high voltages of electricity.
What You Should Know About Outlet Safety
If your home was built before 1960, it likely has at least some two-prong non-grounded outlets, although some may have been upgraded to grounded outlets. Since 1962, the National Electrical Code has required grounded three-prong outlets for new homes built in the United States.
Most residential electrical outlets are connected to circuits of about 120 volts. If more energy than that runs through the wire, the risk of a fault increases. This is why “overloading” outlets by plugging in too many appliances is a bad idea – and it’s an even bigger risk if you overload a non-grounded outlet. If you live in an older home, you need to pay attention to how many appliances are connected to a particular circuit and their total combined voltage.
Watch out for deterioration of wires and their protective insulation. A short circuit in the receptacle wiring, combined with non-grounded outlets typically found in older houses, is a recipe for potential fire and injury.
Replacing Old Electrical Outlets
As long as you only plan to use lower-powered appliances, such as a small lamp, it is probably okay to leave an existing two-prong outlet as it is. If the outlet appears damaged in any way, it is also possible to buy new two-prong outlets as a replacement.
If you need to plug in more “heavy-duty” appliances — like washers and dryers, computers, or big-screen television sets — it’s time to think about upgrading your outlets to include a ground wire. These types of appliances really do require a fully-updated three-prong outlet.
And before you go any further, don’t even think about simply replacing the two-prong outlet cover with a new three-prong cover. That’s nothing but a meaningless cosmetic fix that does nothing to improve safety or function.
Even worse, by merely adding a three-prong cover to a non-grounded outlet, you create an even greater risk of fire and injury when you plug in those large energy-hungry appliances. Now you’re even more likely to be using more electricity than that poor old outlet can take.
One possible fix is to add a Ground-Fault Circuit Interrupter (GFCI). This is a good option for non-grounded outlets located in damp areas, such as restrooms, kitchens, or garages. The outlet will still be non-grounded, but a GFCI will automatically “trip” the circuit – shutting off electrical flow – in the event of a power surge. This protects you from fire and injury.
For other areas of the home, you’ll probably need a full upgrade. Installing grounded electrical outlets is NOT a do-it-yourself project. Only a qualified electrician has the expertise to correctly run a ground wire from the outlet to your electrical service panel. Yes, this can be time-consuming, messy, and it will cost some money. But remember the trade off. In exchange for the one-time payment to your electrician and some temporary inconvenience, you and your family will get the peace of mind that comes with greater safety and a lower risk of damage and injury.
There are three important things to remember here:
- You CANNOT ground a non-grounded outlet without running new wire.
- Each individual non-grounded outlet MUST be upgraded separately
- You MUST hire a licensed electrician to do the job properly.
If you have questions about replacing electrical outlets, including help with upgrading outdated outlets, click here to contact us any time or just call 417-831-8039. We are a certified electrician in Spingfield, MO and can help you.