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Best GFI/GFCI Electrical Outlet Tester

Check all 110V sockets, for under $10

Pretty much everything in our homes is plugged into an electrical outlet.  The outlets are either “standard” or “GFCI”, and you can easily identify the latter by the two little buttons (test, reset) in the middle of the faceplate. GFCI stands for Ground Fault Circuit Interrupter (sometimes shortened to just GFI), which adds an extra layer of protection against electrical shock at the receptacle. (BTW – typically not plugged in devices include your air conditioning / heating units, EV car chargers, ceiling fans and built-in lighting). More on GFCI operations later in this article, here is the recommendation:

Best Choice: Sperry Instruments GFI6302 GFCI Outlet / Receptacle Tester (about $7)

Sperry GFCI Outlet TesterThe Sperry tests both GFCI protected and standard 3-wire120 Volt outlets. Note that while the device is rated for up to 300V, it’s not designed for testing 220V receptacles like those used for some clothes-dryers.

The unit is well made with high-grade plastic and has a good grip from the over-molded soft rubber on the sides. This makes it easy to insert and to remove from outlets, especially older outlets. If you do happen to break the tester, Sperry has a lifetime warranty. Usually all you need to do is email them a photo along with a short description of what happened and they will send you a replacement. It’s that simple.

One nice touch from Sperry is that they printed the wiring fault codes on the bottom of the device, as well as the top. Very useful when you come across an outlet which is installed upside-down (e.g., the ground plug is above the two blade slots).

The 3 LEDs indicate 6 of the most common wiring conditions:

1) OPEN GROUND : Ground wire is not connected
2) OPEN NEUTRAL : Neutral wire is not connected
3) OPEN HOT : Hot (“Supply”) wire is not connected
4) HOT/GRD REV : Hot (“Supply”) and Ground wires are reversed
5) HOT/NEU REV : Hot (“Supply”) and Neutral wires are reversed
6) CORRECT : Receptacle is wired correctly

You’ll find these features on pretty much all of the outlet testers; What makes Sperry our top choice is the GFCI testing feature. To understand how this works in the tester, let’s first explore a little about how the GFCI outlet works.

If the Sperry Instruments GFI6302 GFCI Outlet / Receptacle Tester (about $7) isn’t available, or if you just need one designed for the jobsite, the Sperry Instruments HGT6520, Stop Shock II (about $15) features hi-impact ABS housing with a 250 lb crush rating and the ability to withstand drops of up to 10 feet. Backed by a lifetime warranty this tool will speed up the testing process and increase your productivity for years to come. It also has an audible “beep” to let you know the test is complete.

You’ll find GFCI outlets in your bathrooms and kitchens, since this is where you are most likely to get an electrical shock. The odds are higher for these locations because things get plugged in and unplugged most often – think about hair dryers, curling irons, electric toothbrushes, etc. in the bathroom and coffee grinders, waffle irons, mixers, etc. in the kitchen. Then consider bathrooms and kitchens have sinks, which adds water / moisture in the area. Combine this all together, and the odds go way up for an electrical shock.

When you become the conductor for the electricity, or if you have a faulty device, the amount of electricity flowing from the supply through you (or the device) can be higher than normal. With a standard outlet, this electrical current, if high enough, will cause a circuit breaker in the main load center to “trip” (e.g., switching from “on” to “off”). This shuts off the electricity to the outlet, as well as all the other outlets that are wired to that particular circuit breaker. The main issue in this scenario is that it can take a relatively long time before the circuit breaker trips, which can result in serious injury or even electrocution. It also has the inconvenience of shutting down power to everything on that circuit.

The GFCI is like a local circuit breaker, right at the point of where you plug something in. The GCFI outlet continuously senses the amount of current that is flowing out from the supply wire and what is coming back on the neutral wire. Electricity flows in a loop, so in normal circumstances the current on the neutral should be nearly the same as that on the supply. If there is a large discrepancy, the GFCI outlet senses this excess and “trips”. Basically, the outlet “interrupts” the current flow due to the perceived ground fault.

The GFCI shutting off is similar to the circuit breaker shutting off, which two key advantages. The outlet is at the point of fault, so it reacts much faster to the problem. And since it is a single outlet, it can trip at a much lower threshold than a circuit breaker which needs to support multiple outlets. The result is that you are less likely to suffer harm or electrocution when using a GFCI. Which why most construction codes require GFCI outlets in bathrooms and kitchens.

Now back to the GFCI test feature on the Sperry. Looking at a GFCI outlet, there is a “test” button and a “reset” button. The test button simply trips, or shuts off, the GFCI. So you can test that it is off. The reset button turns the outlet back on after it has been tripped or the test button has been pushed. Basically, you are only verifying that the outlet is mechanically sound and can be switched off / on. These two buttons don’t tell you anything about the electrical state of the outlet.

When you use the Sperry and press the “test” button on the device, you can safely simulate a ground fault condition. The Sperry lets a little extra current flow through it, which should be sufficient to trip a correctly function GFCI outlet. This will let you know that the outlet is electrically good, as well as working mechanically. Remember that you’ll need to remove the Sperry and press the “reset” button on the outlet before it will on again.

If you don’t have one of these yet, just add it to your next Amazon order. The peace of mind knowing that your GFCI receptacles are working properly is more than worth the price of the tester. And the next time something stops working, you can quickly check the outlet to see if that’s the problem. It’s also a great idea to test all of the electrical outlets in your house / apartment, especially if it was built more than 7 years ago or it was recently remodeled. The GFCI outlet buttons should be tested at least annually, and some people recommend as often as monthly (some outlets have problems with buttons jamming, and springs breaking). You just might be amazed at what you find!

Get it from Amazon (about $7), Sperry Instruments GFI6302 GFCI Outlet / Receptacle Tester

Here’s a short video showing how to use the Sperry from the folks at “FIX IT Home Improvement Channel”

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  1. Hannan Ahmad says

    Like other house maintenance tasks, operating GFCI testers make sure that you and your family are protected from ground current. That’s why to maintain this task you should have a GFCI ground tester in your home which are available in electronic equipment selling online/offline market.

    1. Member Technical Staff says

      Hi Hannan – Yes, always a good idea to make sure your outlets are tested periodically for both electrical and mechanical safety.

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