How to Test for Reverse Polarity with a Multimeter

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The electrical system of your home is important for a more convenient living. However, if the electrical work is done by a beginner, there are potential risks, including reverse polarity. Do you want to know what reverse polarity means? Read further. 

Reverse Polarity Defined 

Reverse polarity could happen in your outlets if your electrical wirings were conducted by an inexperienced electrician. With this, some of your home outlets can shock you, which is quite painful and risky. 

If your outlets have reverse polarity, the neutral wire is connected to the right position of the hot wire. In this case, there is always flowing electricity in your outlet. Even your appliance is off. You may not know it, but this is dangerous. 

Reverse Polarity Testing Using A Multimeter 

Do you want to test reverse polarity with a multimeter? You can follow these steps. 

  1. Plug black lead in the middle input on the bottom of your multimeter. Then, you can plug the red lead on the right input. You can now turn on the multimeter by turning the knob in the middle into Voltage AC. 
  2. You can place one lead in the outlet’s longer vertical opening. It is a 0-volt neutral contact. You can also place the other lead on the shorter vertical opening, which is a 120-volt hot contact. If your multimeter shows a reading, then there’s a right polarity since the voltage is transported from hot to neutral contact. 
  3. Place one lead in the neutral opening and the other lead in the ground opening. If your multimeter doesn’t show a reading, there’s no reverse popularity. Thus, the voltage is moved between neutral and ground contracts. Both have zero voltage. 

Why Is Reverse Polarity Dangerous?

It is important that the neutral and hot wires must be connected to the right terminals in your home’s electrical receptacle or circuit. If not, there will be a reverse polarity that can shock you. It can even cause potential hazards to your home. 

With reverse polarity, there’s still current flow in your outlet when your appliances are supposed to be off. Meanwhile, even though there’s no current flow, if you accidentally touch the damage or wrong part of the device, accidents can happen. The reverse polarity on your electrical outlet can lead to fire, shock and short circuit. Even a simple floor lamp is not safe in reverse polarity. 

Another disadvantage of reverse polarity is that it can cause damages to your appliances as well as other electronic devices. If the live voltage is present in the wrong place of the circuit, it will make the device stay energized even if it’s already switched off. There is also a high chance of electric shock hazards and overheating. 

What Causes Reverse Polarity? 

Reverse polarity can bring hazards to your electrical system. It can damage your appliances, devices, and even cause harm to you and your family. Some of its causes include:

  • The reverse polarity can happen when the white and black wires were reversed in the circuit or between 2 receptacles in one circuit. 
  • It is wrong to connect the black wire to the silver screw. Similarly, the white wire should not be connected to the wire that goes to the brass screw. 
  • It can happen if both white and black wires are wrongfully attached to the electrical panel. 
  • The reverse polarity occurs if it is visually hard to determine which is the white and black wire in an old electrical circuit. Meanwhile, it is easy to identify the hot wire using VOM, neon tester, electrical tester, or DMM by checking the current flow or voltage between a single wire and ground. 
  • Another cause is when someone doesn’t have the knowledge about the right connections for the multiwire branch circuit or red wire in a 3-wire circuit. 
  • Reverse polarity is possible if there are some errors in the wiring in a circuit. An example of this is when there’s unexpected current on supposed to be of a neutral wire in an electric circuit. 

Reverse polarity could cause harm to your home. If not given quick action, it can lead to fire and other hazards that can bring you regrets and disappointments in the end. It can cause death, as well. For sure, you don’t want these potential problems to happen. With that, you must be responsible enough to fix your reverse polarity as soon as possible. 

Another solution is to conduct a reverse polarity testing using your multimeter. You can follow the steps mentioned earlier to determine whether there is a faulty wiring or connection in your electrical system. It is important to learn if there’s a reverse polarity to make sure that your home is safe from fire and other possible hazards. 

Polarity Testing 

Polarity testing is essential to ensure if you have the right electrical connection. With this test, you can determine if the installed switches in the system are attached in the current-carrying conductor and not in the neutral. If you don’t have the knowledge about the polarity, you can experience electric shocks especially in the maintenance process. 

Even more important, you must also know how to use your multimeter to fix your reversed polarity. With that, you can safely fix the damage in your electrical circuit or outlet. Moreover, you and your family are also safe from any fatal accidents caused by reverse polarity. Meanwhile, the polarity testing can also be conducted using different methods. These methods include continuity testing, visual inspection, and live testing. 


If you want peace of mind and more convenient living at home, it is advisable for you to conduct reverse polarity testing using your multimeter. This will help you to prevent unnecessary expenses in the future that can be caused by reverse polarity. Your home must be a safe zone, so make sure that you have proper polarity for your electric circuit or outlets. It is beneficial to prevent damages for your appliances and other electronic devices. 

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