A Word About Receptacle Testers

Concerning the Sperry Instruments GFI6302 GFCI Outlet / Receptacle Tester:


Out of the package, with minimal understanding of operation, this one isn’t a good choice, here’s why in my opinion —

After buying this (and it’s a lovely, practical, pleasing design), the very first use, I experienced a receptacle similar to one that a reviewer claimed caused him to fail a Home Inspector Test, he thought the receptacle wiring was good, the instructor’s receptacle tester showed an open ground.

With this tester, a receptacle with an open ground, brightly lights one bulb, one slightly less bright, and one dim. I bought this tester to replace one that I had lost but has since shown up. Comparing it now, the older one only lights one bulb for an open ground. As we were working to get a contractor to rewire the house, I mentioned this effect to several electricians, and their socket testers, different models, only lit one bulb too.

In the image below, Sperry Instruments GFI6302 GFCI Outlet / Receptacle Tester is on the Right, my old tester on the Left. A single lit bulb in a specific location on either one indicates an open ground. As can be seen, the Sperry lights the center bulb brightly, which according to the chart on the tester is an open ground when only the center bulb is lit, but the other bulbs are lit as well, just not brightly, and that’s confusing.

My older tester is on the Left, one bulb lit, and on that tester, that single bulb being lit indicates an open ground.

Mind you, some reviewers where we bought this are fond of the Sperry Instruments model GFI6302 GFCI Outlet / Receptacle Tester, but careful attention needs to be given to the brightness of the bulbs. One article online said not to use any receptacle testers, but I disagree. As an industrial electrician, we have these, but we usually use a voltage tester, but you have to know what to expect, and exposed voltage tester lead ends are hot when plugged in, so shock and shorting hazards exist. Receptacle testers work just like using a plug, so it’s safer. There’s one site online that has an extended chart of conditions, and what to expect from the lights, including dim lights. It’s worth the effort to review it, makes this tester easier to use and understand, see it at the following link:

What the Outlet Tester Means – Interpreting 3-Prong Receptacle Testers

I purchased another receptacle tester on Amazon, it has 5 lights, but only one lights for each defect, and a green light for good. It’s a keeper. Big, but I love it.

My new one, the “Sperry Instruments HGT6520, Stop Shock II – Single LED Indicator, GFCI Outlet Tester” available on Amazon, has multiple LEDs, only one lights for any one condition, that condition is marked by each light (no table to consult), the LEDs are red to denote a defect and green for correct wiring, even from a distance in the photos below, the green is easily visible. In addition, the tester requires the circuit to have less than 10 ohms resistance to denote a normal ground, so poor ground conditions are flagged too, not just missing grounds.

Wiring Testing

Here’s a visual comparison of all three, they all test the GFCI function of receptacles as well, Providing the Receptacle is Grounded Properly!!! GFCI Receptacles DO NOT need a ground to work, the test button on GFCI receptacles will work without a ground, but, EMPHATICALLY, GFCI Receptacle Testers that plug into the Receptacle need the ground to be good to test the GFCI function of the receptacle.


Of using Receptacle Testers in general, this review is noteworthy.

I bought this while looking for homes to buy. It is a good indication on how well a person takes care of their home. Typically, an electrician won’t mess up something as simple as an outlet. A reversed ground or mixed up outlet is a great indicator that the person you’re buying from is a DIYer. Those types (DIYers) can be great for home maintenence, but if a wall plug is overlooked, then you might want to look closer at other things as well.

Pursuant to this reviewers comments, on the home were were buying, we found a multitude of open grounds (turns out the home was almost entirely on Knob & Tube wiring), so those deceptive modern receptacles were installed where old ones existed and have no ground because of the Knob & Tube wiring, and we found one Hot and Neutral Reversed. There was extensive former owner tinkering with the wiring, and it should’ve been a red flag to avoid a home that took months to get ready to live in (availability of the electrician) and much more money than we ever envisioned.

Hot and Neutral Reversed


Home buying? Get a good tester, check out the receptacles, write down your findings, and have the service and breaker panel checked by a trusted electrician as well.

Author: Dr-Artaud

A Doctor that is not a Doctor, but named after a character in the movie "No Such Thing", as is the Avatar.

6 thoughts on “A Word About Receptacle Testers”

    1. Hi Ramses. I was removed as a member by the web site, I was told I was saying things about them on GAB. I’m at a loss about what they were talking about. They threw a few more insults, I didn’t respond to them, it just doesn’t pay.

      I spent over an hour doing the weather for the site, to give them a regular feature, and that was done 7 days a week for months. I’m not sure how they could have felt that I didn’t respect the site, I thought the world of it, it is superior to GAB for the material I posted. I could embed HTML Links, it handled images very well, and the length of the articles in Characters was seemingly unlimited. After I left, I’ve looked in, and on 2 occasions I happened to see, the Weather Map was the wrong one for the day. I thought people really liked seeing the Severe Weather Potential, and the usual rain and snow trends.

      The Device I wrote about here checks receptacles to see if the Ground is Good, the third prong on some plugs in America is the ground. Having a Grounded Plug in an Ungrounded Receptacle is dangerous since the ground doesn’t work.
      These also Test GFCI Receptacles, they kind that open if you get shocked under some circumstances. In England they are called “RCD”, Residual Current Devices.

      Wiring in the U.S. and England in homes has one Hot Wire and one Neutral Wire. Once connected to a Receptacle, this Tester makes sure it was connected to the correct screw.

      The U.S. Uses 120/240 Volts, coming into homes, and the U.S. uses 230 Volts, but both countries have Neutrals. I’m not sure what they use in Spain. The U.S. Uses Branch Circuits, fused to 15 Amps, U.K. Uses Ring Circuits, fused to 30 Amps, and each Plug has a Fuse in it. In America, if the Breaker Trips, you have to remove the shorted device, then find the lighting panel, usually in the Basement, and reset it. In England, they offending device will blow the fuse in the Plug and Shut-Down, leaving the Ring Circuit with power.

      I hope you’re ok, I hope things are calming down there. Great to hear from you.

      Electrical Wiring Colour Guide For The UK

      Liked by 1 person

    1. Thanks, I never knew where they used those. The recessed design makes it safer, but since England uses Ring Circuits, they have much more current and shorts are much more likely to be bad. But Spain, and England, seems to have put much more thought into the plugs and receptacles than the U.S. has.

      Just for fun:

      Plugs and sockets of the U.S.

      Plugs and Sockets of the World.

      Liked by 1 person

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