Skip to main content

How to Tell If Metal Box is Grounded

By November 12, 2020September 3rd, 2021Electrical
How to tell if metal box is grounded

When building or buying a new home, you want to make sure that everything is properly in place. Things such as the countertops are level, the cabinets are straight, but did you think about the electrical units? 

The metal box is behind the outlets on the walls and the purpose is to hold the wires and outlet and connect it via a ground wire to the breaker box.  During the walkthrough of the home, the testing of the circuit breakers is complete, but how can you tell if the metal box is grounded?

Purchasing a tester at a hardware store is where you can start to see if the metal box is grounded.  Why is this important and what does the tester tell us and what steps do you take to tell if a metal box is grounded?

Why This is Important

A grounded metal box is important to have as it sends the electricity through the ground to the breaker box that is also grounded.  Surges in the electricity a box that is not grounded allows the electricity to go where it wants to.  This is not a good thing and can cause electrocution or fire.

The Tester and How to Tell If the Metal Box is Grounded

As mentioned above you can buy a pigtail tester at the local hardware store or one like this on Amazon .

How to test the metal box to see if it is grounded

How to Test the Metal Box to See If It is Grounded

  1. Shut off the power for that room
  2. Pull off the outlet faceplate and then pull the outlet out of the wall
  3. Unscrew the wires so they are not attached to the outlet anymore
  4. Check that the positive and neutral wires are exposed and not touching anything. Turn back on the electricity for that room
  5. Touch one end of the tester to the hot wire (black or red wire)
  6. Touch the other end of the tester to the metal box inside the wall
  7. If the tester shows voltage on the screen, then you know that it is grounded.

Note: These directions may vary depending on the type of tester you purchase.


Here is a great video that shows how you can tell if an electrical box is grounded.

Unfortunately, the steps above are not done on homes so homeowners don’t know what dangers could be lurking.  It is a good idea to share this information with others so they know that their metal box is grounded. Injury or even death does not need to happen if the tests are done to make sure the metal box is grounded.

What If it Doesn’t Light Up or Show Voltage?

If the tester doesn’t light up or show voltage, then it is not grounded.  However, make sure before you draw this conclusion that you are touching a hot wire. You will need to contact a professional to help ground it. Sooner than later is better as any surge can cause a fire or electrocution.

Two prong outlet
Two prong outlet

Two Prong Outlets

Maybe your outlet is two prong instead of three and it isn’t working? Two prong outlets are never grounded and calling a licensed electrician to evaluate or repair the issue is a good recommendation.

Uncovering Other Issues While Testing That the Metal Box is Grounded

If you find while testing the outlets that there are issues or damage to the electrical system, you will want to contact a home inspector. For instance, homes built between the 1950s–1980s have a chance that they have an FPE Panel. If it does, then you need to contact a home inspector to check it out.

Maybe you are finding an issue with a few outlets and the home was built after February 1998? You would want to make sure that you don’t have the Challenger GFCI breaker that has been recalled. If you do, you will need to contact a home inspector.

Do you have questions about the above steps, finding issues, or would like an inspector to check your home wiring for you?  Leave us a reply below so we can help!


Leave a Reply