Reverse polarity may not seem like a big deal, but it is. What this means is that an electrical outlet or light fixture is wired backwards. There is a “hot” side and a “neutral” side to these electrical fixtures, and it is important that the wiring is connected correctly. Although the circuit will still work if wired backwards, having the hot and neutral reversed can create a dangerous situation most people are never even aware of.
How do electrical outlets and light fixtures work?
We should probably understand how an electrical outlet and light fixture work before moving on to reverse polarity. Basically, they are designed for electricity to run through them in a certain way. Let’s use the kitchen sink as an analogy. Water is supplied by the faucet (hot side) and exits through the drain (neutral side).
Electrical Outlets
When you look at an electrical outlet, you will notice that one of the slots is longer than the other. The slot orientation determines the polarity. The shorter slot is the hot side, also known as the ungrounded conductor. The long slot is the neutral side, also known as the grounded conductor. The little “doghouse” at the bottom is the ground wire, which is literally connected to the earth. If the electrical outlet is wired correctly, the hot side will have a black or red wire attached to it, and the neutral side will have a white wire attached to it. The ground is typically a bare copper wire.
Why does reverse polarity matter?
Let’s say, for example, that you have a lamp plugged into an outlet. In a properly wired electrical outlet, the hot wire is connected to the lamp’s switch. Until the switch is turned on, there is no power to the lamp socket. Once the switch is turned on, the power will travel through the hot wire to the lamp socket, lighting the bulb, then to the neutral conductor.
Wired backwards
If the electrical outlet is wired backwards, meaning reverse polarity, the hot wire is connected to the socket, not the switch. This means that the socket would have power all the time, even if the switch is turned off. In the event that someone is changing a light bulb, all it would take to complete the circuit to ground and get a shock is to touch the metal in the light socket.
Example
Another example would be your toaster. If it’s plugged into an electrical outlet that has reverse polarity, the power would go directly to the toaster coils (the part that gets red hot when toasting), even when the toaster is switched off. So, you put in some bread, turn the toaster on, the circuit is completed, and all seems fine. Your bread toasts, the switch turns off, and the coils are no longer red. But let’s say your toast gets stuck. You grab the butter knife, slip it into the toaster to dislodge the toast, but accidently come into contact with one of the coils. Boom! You get a shock! You have become the ground conductor! If the electrical outlet was wired properly, the power would be at the switch and the coils on the neutral side of the circuit.
As a homeowner, how do I check for reverse polarity?
An easy way to check the outlets in your home for reverse polarity is to purchase an outlet tester. These handy little devices are relatively inexpensive, easy-to-use, and can be purchased online or at a local big-box home improvement store. The indicator lights on the tester will show if an outlet is wired correctly, has an open ground, an open neutral, an open hot, or is hot/ground reversed or hot/neutral reversed (reverse polarity). If the tester indicates there is a problem, you should call an electrician to recheck the outlet and make repairs as needed.
Summary
Although an incorrectly wired electrical outlet may seem like a small thing, it can be a hidden danger that can cause electrical shock, serious injury, or worse. When performing a home inspection, our home inspectors check every outlet they can safely reach and document any of the above-mentioned issues.
At HomePro Inspections, our home inspectors are trained and always look for electrical outlet and switching issues when inspecting a home. All issues are documented in your home inspection report 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 utilize our online “Schedule Now” feature to set up an appointment.