Disclaimer. This article is written and uses terms not necessarily technical, but easy to understand.
When we are inspecting a house, we here at Beagle Home Inspections, LLC check every accessible electrical outlet. We check the top and bottom of each outlet. An issue we find is that the hot and neutral wire have been reversed when connected to the outlet. This is called reversed polarity. While your electrical device will operate, this reversing of the hot and neutral wires creates a shock hazard.
Definition of hot and neutral wires.
A standard electrical outlet has 2 wires that conduct electricity. One wire is connected to the earth or grounded. This is commonly called the neutral wire. It is usually white. It is connected to the large slot on the outlet. The electricity flows from the outlet back to the electric panel through this wire.
The other wire is not connected to the earth or is not grounded. Sometimes called the hot wire. It is usually black, sometimes red. Electricity flows from the electric panel to the outlet through this wire. It is connected to the small slot on the outlet.
Outlets are polarized to make electrical devices safer. You can only plug into the outlet one way.
When the switch is open no electricity flows to the electrical device. When the switch is closed, electricity flows though the electrical device and powers it then flows back to the panel box. Electricity will flow and power the electrical device whether the outlet is wired correctly or reversed.
The direction of flow.
The flow of electricity comes in through the hot wire, through the electrical device and back to the electrical panel through the neutral wire.
If the wires are reversed the flow is in the opposite direction.
When the wires are reversed the shock hazard comes into play. Electricity is constantly waiting to flow. So, when the wires are reversed the electricity is flowing through the electrical device and waiting for the switch to close. If you touch the device and you are in contact with the earth or grounded the electricity flows through, you.
Also, because the electricity is constantly flowing through the device, it can decrease the life span of the device.
The fix can be as simple as reversing the hot and neutral wires at the outlet. But sometimes the reverse is up steam of the outlet. Finding where the reverse is and fixing it is not for amateurs. Get a professional to do it.
The takeaway is reversed polarity is a shock hazard. Outlet testers are inexpensive and can be bought at any home improvement store. You can test yourself, for peace of mind, but if you find a reversed polarity outlet, call a professional.
Just because it “works”, doesn’t mean it is wired properly.