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I conducted an experiment in which I tested receptacles with different wiring problems. I tested each wiring configuration with both a three-light tester and a SureTest circuit analyzer model 61-164 from Ideal Industries.

3 light testerIn this post, I will show the results of each of these tests so that you can see the advantages and the limitations of these two devices.

But first, a brief introduction.

Three-light testers are devices used by many home inspectors, electricians, and handymen to test electrical receptacles.

There are several reasons that they are so popular:

  1. They are simple to use.
  2. They are cheap, costing as little as about $10.

The other tester is the SureTest circuit analyzer model 61-164 from Ideal Industries. It can do a lot of things that the three-light tester cannot do. As the name says, it is a circuit analyzerSureTest circuit analyzer

If you are simply wanting to know if a receptacle is properly wired, the SureTest circuit analyzer will tell you. It can also measure voltage drops, tell you how fast a GFCI receptacle trips, measure resistance on the hot, neutral, and ground wires, etc.

While all of this information may be useful for some people, it is a lot more information than most home inspectors and handymen need to know.

An advantage of the Suretest over a three-light tester is that it can identify some deficiencies that a three-light tester cannot identify.

The biggest disadvantage to a Suretest is its cost. It costs about $300 compared to $10 for a three-light tester.

Another disadvantage is that the SureTest takes 10 – 15 seconds to analyze a receptacle while a three-light tester does its thing instantaneously.

The Results –

I wired up my test receptacle with various wiring configurations. Then I plugged each tester into the receptacle to see what indication they would give.

Here are the indications that each tester should give for different wiring configurations.

3 light tester indications
suretest light indications

Results of the tests:

Properly Wired-

3 light tester- properly wired

Correct Indication

suretest- properly wired

Correct Indication

As you would expect, both testers gave the correct indications.

Open Ground-

3 light tester- open ground

Correct Indication

suretest- open ground

Correct Indication

Again, they both gave the proper indications.

Open Hot-

3 light tester- open hot

Correct Indication

SureTest- open hot

Correct Indication

An open hot is just a dead receptacle, so both testers should have, and did, show nothing on their displays.

Open neutral with no load –

(On this set up, I disconnected a neutral wire upstream of the receptacle and had no load plugged downstream of the receptacle.)

3 light tester- open neutral no load

Correct Indication

On this one, it takes two photos to show the indication that the Suretest gave. The Suretest screen was mostly blank, but about every two seconds the screen would briefly flash what you see in the second photo.

suretest- open neutral no load
suretest- open neutral no load

Wrong Indication

This is the first situation where the three light tester outdid the SureTest. Yes, the three light tester was accurate while the Suretest told you nothing useful.

Open neutral with a load plugged in and turned on –

3 light tester- open neutral with load

Wrong Indication

suretest- open neutral with load

Wrong Indication

Here is another instance where the three-light tester is more accurate. Although it shows that we have a hot/ground reverse which is wrong, at least it shows something, while the Suretest is completely blank giving us no indication at all.

As long as you keep in mind that a “Hot/Ground Reverse” indication actually means an Open Neutral, then the three-light tester will tell you what the problem is.

I have another post that talks all about why an open neutral will give an indication of a hot/ground reverse. You can read post that here- hot/ground reverse post.

Hot/Neutral Reverse (Reverse Polarity) –

3 light- hot/neutral reverse

Correct Indication

Again, on this one, it takes two photos. The “H” and “N” lights are flashing on and off alternately, indicating the hot/neutral reverse.

suretest- hot neutral reverse
suretest- hot neutral reverse

Correct Indication

For this wiring configuration, both testers gave the accurate indication of the defect.

Open Ground and Reverse Polarity Combined –

3 light tester- Open Ground and Reverse Polarity Combined

Partially Correct

suretest- Open Ground and Reverse Polarity Combined

Partially Correct

The three-light tester and the circuit analyzer both only recognize and indicate that the receptacle has an open ground. Neither of them identifies that the receptacle is also wired with reverse polarity.

Bootleg Ground –

A bootleg or false ground is a dangerous situation which you will likely encounter at some point. If you are unsure what it is, you can read about bootleg grounds here.

3 light tester- bootleg ground

Wrong Indication

suretest- bootleg ground

Correct Indication

The three-light tester cannot identify a bootleg ground. As you can see, it simply indicates that the receptacle is properly wired. This is one of the weaknesses of the three-light tester.

The Suretest circuit analyzer properly identifies the bootleg ground and indicates this with the flashing “F” shown in the photo.

This table summarizes the indications that both the three-light tester and the SureTest circuit analyzer give for various wiring configurations.

Wiring Configuration

Three-Light Tester

SureTest Circuit Analyzer

Correctly wired Correct indication Correct indication
Open ground Correct indication Correct indication
Open hot Correct indication Correct indication
Open neutral, no load Correct indication Blank (with quick flash)
Open neutral, with load Indicates hot/ground reverse Blank
Reverse polarity Correct indication Correct indication
Open ground & reverse polarity Indicates open ground only Indicates open ground only
Bootleg ground Indicates properly wired Correct indication

Hopefully, this post will help you to see the limitations of the two types of testers. All-in-all, the SureTest circuit analyzer and the three-light tester seem to be about equal based on my tests. While they both correctly identified five situations, they each have their own limitations. 

The only configuration indicated correctly by the Suretest that was not identified by the three-light tester was a Bootleg ground. Is this one deficiency worth paying about $300 more to identify? You will have to make that decision for yourself.

© 2021 Mike Morgan

This article was written by Mike Morgan, the owner of Morgan Inspection Services. Morgan Inspection Services has been providing home, septic and well inspection services throughout the central Texas area since 2002. He can be reached at 325-998-4663 or at mike@morganinspectionservices.com. No article, or portion thereof, may be reproduced or copied without prior written consent of Mike Morgan.


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