Can you explain a bit more about the readings of an outlet tester?

Today, with many people looking to do simple wiring jobs at home on thier own, outlet and GFCI testers are becoming more and more common tools in the home owner’s tool box. That being said, many people purchase the tester to inspect outlets or check the work they have done, but they are not 100% sure as to what the tester is telling them.

Below is a picture of the wiring of a standard wall receptacle that you would most likely find in your home. As you see, there are three different wires that should be connected to your receptacle. There should be a black, a white, and a green wire attached securely to each receptacle.


Each of these wires has a different purpose, and are vital to ensure that your appliances that are plugged in are properly powered and grounded, as well as providing you with safe connections for these appliances so that you do not recieve an electrical shock.

Black(Hot)- This is the wire that is carrying the voltage to your appliance. This is commonly referred to as the “Hot” wire because it is the wire that is carrying the voltage.

White(Neutral)- This wire is the wire that allows the voltage to return to your panel.

Green(Ground)- This wire is a safe return for voltage if the neutral doesn’t properly function. This wire allows the voltage and current to return to ground without shocking the user.


My outlet / GFCI tester shows all 3 lights lit, what does that mean?

Normally when you see this, the first thing that you will want to check is all of the connections on the back of the receptacle, and if all of those are tight, then check the rest of the receptacles in the circuit.

– Many times when you see this, there is a loose neutral connection on the receptacle.

– You will also want to make sure that you do not have any other appliances or electronic devices plugged in on the circuit. Sometimes components inside of these products can create feedback or leakage to another wire that will give these types of testers problems.

– Plugging into a 12V DC to 120V AC converter will also have this issue.

If none of these steps resolve the issue, then we recommend that a licensed professional examine the situation for you.

What are the different combinations/color codes on my outlet/GFCI tester and what do they mean?

Sometimes these marking can be hard to read, below you’ll find the exact indicator and fault measurements along with what they mean.

Color Code: Red, Yellow / Orange & White (clear)

These are the colors you should see on the tester. Red is the most obvious of the colors, but yellow on the break down translates to orange on the tester. This happened because orange clashes with red and doesn’t show up as well. White or clear means that there should be no light at all.

Indicator   Fault
0ff 0n 0ff  Open Ground
0ff 0ff 0n  Open Neutral
0ff 0ff 0ff Open Hot
0n 0ff 0n  Hot/Ground Reversed
0n 0n 0ff  Hot/Neutral Reversed
0ff 0n 0n  Correct

Open Ground: This means that the ground wire is loose or has not been properly connected.

Open Neutral: This means that the neutral wire is loose or has not been properly connected.

Open Hot: This means that the hot wire is loose or has not been properly connected.

Hot / Ground Rev: This means that the ground and the hot wires are reversed or shorted somewhere in the circuit.

Hot / Neutral Rev: This means that the hot and neutral wires are reversed or shorted somewhere in the circuit.