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What is this outlet with test and reset buttons for, exactly?

November 15, 2016
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If you’re in your bathroom or kitchen, you’ve probably noticed outlets with ‘test‘ and ’reset’ buttons on them. This outlet, called the Ground Fault Circuit Interrupter (GFCI) outlet, is designed to prevent electrical accidents. Different from a fuse, which is designed to prevent electrical fires, GFCI outlets are designed to prevent injury from electrical shock. Because water is a main cause of ground faults, national electricity codes were updated in 1971 to require GFCI outlets to be used anywhere the electric current may encounter water. Kitchens, bathrooms, laundry rooms, near swimming pools, and even unfinished basements must have GFCI outlets if they’ve been built or remodeled since 1971.

What is a Ground Fault anyway?

As electricity comes out of an outlet, it follows the easiest path of toward the Earth – or ground. Normally that path is through the copper wires we use for powering our homes; however, in the case of a ground fault, the electricity takes a shortcut through something else—like a person—to get to ground. A ground fault can happen because of a number of reasons, such as:

  • Faulty or loose wiring in what is plugged into the outlet
  • Presence of water near the electrical device or outlet
  • Old or ungrounded electrical wiring

GFCI outlets “weigh” the power in and out

The two flat prongs on your plugs are for carrying positive and negative charges, which means the power from your electrical service box leaves the outlet from one prong, travels into your plugged in device, and returns through the other prong back to the service box. Without the return trip, your devices wouldn’t work.

The GFCI outlet was designed to measure the power flowing in and out of the plug to make sure there is a balance. It measures electrical charges as small as 5 milliamps for any variation and when it finds a difference, the outlet “pops”, or breaks the flow of electricity.

So, let’s see this in action: if a hair dryer drops into a sink full of water, for instance, the electricity will fault to a new ground through the water. After all, it’s an easier path to ground than routing all the way back through the house. The GFCI outlet senses that there has been less electricity coming back through the outlet and completely stops the power flowing to the device. This process takes less than one-tenth of a second. In fact, it’s saved an estimated 1,000 lives, in the United States,  since its nationwide adoption in 1971.

Test and reset for peace of mind

Because a popped GFCI outlet no longer carries an electrical current, Charles Dalziel – the inventor of the GFCI – decided to make a way to repair, or reset, the outlet after it has popped.

The element inside the outlet is fairly easy to reset with a simple mechanism, so a reset button was added to the outlet. Then, to give the user reassurance that the outlet is functioning properly, the test button was also installed. Later models of the GFCI include a tiny LED light for even more assurance to whether or not the outlet is live.

To test your GFCI outlet, simply plug something in and press the button labeled ‘test’. If what is plugged in stops working, your GFCI is working properly. To make the outlet active again, simply press the ‘reset’ button.

Protect your outlets

The GFCI outlet is a remarkable invention that can save your life in a click. Give yourself peace of mind by running a simple test, and then reset it as needed. We think making life simpler and safer is always a good idea, which is why many of our Home Protection Plans include your electrical outlets in their coverage. So, if you have an electrical issue, it only takes one call and we coordinate a licensed technician, pay their fee up to the complete coverage amount, and guarantee that repair for a full 12 months. Learn more about our Home Protection Plans or give us a call at 888-995-0992 to learn more.