Is Reverse Polarity Detected During A Home Inspection Ok?
As a home inspector, it is my obligation to test a sample of outlets during a home inspection. Often times there is amateurish wiring and mistakes are made when installing an outlet. I can identify this with a receptacle tester by the light code (good or bad) portrayed when it is plugged into the outlet. This is referred to as reverse polarity and it can cause a potential shock hazard, however, it is not complex and usually simple to repair yourself.
What is reverse polarity?
On a typical outlet there are two wires that are carrying electricity to the receptacle; this is typically called a duplex receptacle. The white wire is the neutral wire and is grounded to the earth. The second wire should be black or red - and is not grounded. This is the hot wire and it completes the circuit by coming in contact with the ground. If you touch the hot wire and you are grounded, we usually stand on the ground/earth, you will be attached to this loop or circuit. This will result in a shocking experience.
Electrocution hazard example:
Let's say for example, you are working on a kitchen appliance and it is powered off. You would think sticking a knife it it (for example a toaster) would be safe - because it is "off." If the receptacle had reverse polarity, the heating element would be shut off. But unfortunately, the neutral wire would still be hot. This is tricky because although the appliance may not be functioning, the electricity is still live and you can be zapped/shocked.
How can I make sure my outlets are safe?
Short answer, hire an electrician to inspect them and the feed wires. However, if you do some research on your own: the the repair is fairly straightforward. There is a lot involved in working with electricity and it all starts with shutting off the main breaker before you take anything apart. You also need to know how and what wires go where so do you not create more problems when you're done. Reverse polarity can be a result of a misconfiguration of the wires upstream from that outlet. You can have a domino affect and you may not be able to fix the reversed outlet just by swapping the wires around.
Reverse polarity is an electrocution hazard and should be repaired immediately by an electrician. Just because the outlet works, doesn't mean it is safe. You can buy an outlet tester for a few dollars at your local hardware store and test yourself to make sure you do not come across this problem in your home.