Why Do Some Outlets Have Red And Black Buttons? Here's What They Actually Do

Have you ever noticed how some electrical outlets in your home look slightly different from the rest? Instead of a smooth plate, these outlets feature two small buttons, often colored black and red. They are called Ground Fault Circuit Interrupter (GFCI) outlets, a built-in safety device for your home's electrical system. Those two buttons are not a random design quirk, but a necessity to prevent a shock or electrocution. And to properly understand them, we first need to learn how GFCI works.

These outlets are typically mandated by building codes, but what exactly is a GFCI receptacle and where in your home should they go? Well, they are most commonly installed anywhere electricity is needed near a water source. Unlike a standard circuit breaker, which prevents house fires from overloaded wiring, a GFCI focuses on protecting people. It constantly monitors the flow of electricity, comparing the current traveling out to an appliance with the current flowing back in; in a normal circuit, these currents must be equal.

The mechanism is surprisingly fast and precise. If the GFCI detects even a minuscule imbalance (as little as five milliamps), it means electricity has found an unintended path, likely through something like water or a faulty appliance. When this happens, the GFCI reacts instantly, cutting the power in a fraction of a second (also known as a trip). This swift interruption is usually enough to stop a dangerous or fatal shock, which is why understanding the buttons that control this critical safety feature is essential for every homeowner.

The red and black buttons are your direct interface with this safety system. They give you both the ability to restore power after a trip and, more importantly, to verify the GFCI outlet is functioning correctly. The red button is the reset control, and is labeled "reset" (it can also be white, and should protrude slightly when tripped). When the GFCI mechanism detects a dangerous current imbalance, it trips the internal breaker, which causes the reset button to pop out, shutting off power to the outlet and anything connected downstream. To restore power, ensure the water or appliance issues that caused the trip have been resolved; from there, just press the reset button back into the outlet until you hear a solid click.

The other button, usually black, is the test button and is labeled "test." This control is designed to simulate an actual ground fault. When you press the test button, it briefly creates a deliberate current imbalance — like what could occur if a plugged-in appliance fell into water — forcing the GFCI to activate its protective shutdown. If that outlet is working properly, pressing the test button will immediately cause the reset button to pop out, and power from the outlet will be cut. If you push the test button and nothing happens (so, the power stays on and the reset button does not pop out), it means the GFCI failed and needs to be replaced immediately to keep your home safe. 

The contrasting colors of GFCI outlet buttons, typically red and black, provide an intuitive visual indicator for the two opposing functions. Red is often associated with warning, emergency, or stop, signaling that the button that restores power is currently engaged or needs to be pressed. Black, representing a neutral function, is designated for the test feature. This simple, standardized user interface allows any homeowner to quickly and easily identify which button restores service and which confirms the device's protective capabilities.

As indispensable as GFCIs are, they can eventually wear out over time. This is why the test button is a critical safety feature that homeowners should utilize regularly. Safety experts and manufacturers strongly recommend testing every GFCI outlet in your home at least once a month. This simple routine only takes a few seconds, but gives peace of mind. You can even bundle the chore up with checking your smoke and carbon monoxide detector batteries each month. It is an easy way to keep items in your home that can save your life at a moment's notice ready to do so. If any of your GFCIs stop working, call a professional to help you troubleshoot your faulty outlet and discuss potential replacement.