What Can be the cause of this

When using my handy outlet tester today The lights on the tester would not come on unless I jiggled the plugin tester. Example: an outlet kept showing an open ground until I jiggled the tester. Then the it would go to normal until I let go of it and then it would show an open ground again. My tester works fine at home. The home was built in 1975. Any thoughts. This happend on several outlets.

Sounds like you may have found some worn out recepts.

Or a poor back stabbed connection/loose wire.

That’s what I thought, too.


Hand held outlet testers should be calibrated with another tester on a regular basis. Many times older ones wear out because of the amount of use. All inspectors should carry two of these testers for this reason. There is nothing as embarrassing as a house with open grounds throughout only to find out the bulb on the tester was broken.

I am assuming the wiring at this house is not aluminum or aluminum with copper crimps. This type of wiring was used a lot around this era and this type of defect is common. Connections loosen because of heat build up. If aluminum wiring was present, were the receptacle covers hotter than normal. We use infrared temperature guns on all receptacles and breakers where aluminum is present. The average temperature of a breaker in use will be between 75-80 degree F. Outlets will be approximately the same.



Michael: What would be the approximate difference in temperature between a copper wired receptacle vs. an aluminum wired receptacle? Or one with a loose connection? Is that with a device plugged-in and turned on or no device plugged in or on?


Good question I would like to know also.


The temperature should be the same (i.e. within acceptable range) if everything is working correctly. That is why aluminum wire sizes are larger than that of copper. Remember the smallest copper conductor is #14. Aluminum is #12. All the aluminum problems occurred because original designs expected aluminum wiring to perform at the same efficiency as copper. It only took a few house fires before it was realized that the degree of thermal expansion and contraction was much greater for aluminum, thereby resulting in loose connections, arcing etc.

Remember also that the temperatures I gave you earlier are from experience. If you test every electrical panel and visible receptacle and the average temperature youe experience is 75-80 degrees or even 85 degrees, then it would be fair to assume that an issue may be present when temperatures greatly in excess of these numbers are recorded. This is what I call a calculated assumption. In other words you can back up your conclusion.

When devices are plugged into the circuit, temperature increases will be experienced. Slight variations to the above numbers are probable which are normally not a big deal. If the circuit is at its maximum, which I believe is 80% (but will vary) of the rated number, you will feel and hear a little vibration at the circuit breaker.

Always take an amperage draw at the panel to determine what the amperage of the circuit you are reviewing is. You should also photograph situations of higher temperatures or amperage. I once found a main disconnect reading a temperature of 198 degrees. Of course the electrician for the seller said there was nothing wrong. With photographic evidence, I backed up my comments and the entire panel was replaced. Rheostats are often found to be over heating where installed by homeowners.

While the phrase, “further evaluation” to realtors in our area today is like a red rag to a bull, there are exceptions. Where a potential safety issue is at hand then this would be one. (The reason FE is frowned upon is because of the influx of new inspectors and their lack of understanding on software boilerplate comments)

Joe T. would be a good reference here for further information on this topic.

Hope this helps.



I assume when you suggest using an amp probe for a circuit, you are speaking of one where you noticed a thermal problem (noticeably higher temps than the rest).

Even this action exceeds most HI org standards of practice, so it is not required. That’s not to say that it isnt a good thing to do, though. I do question the need to check all circuits in this manner.

2 New GFCI Testers in a Duplex Receptacle

Hay Gary. i posted (about a month or so ago) about a little practical joke i like to play on newbies with my volt stick. if you complete the circut with your hand (push clip and with other hand touch tip) the light lights. fun, but also a good lesson in electronics. anyway, is it posible that a similar situation was happening to you? maybe just wiggleing it made enough of some weird magnetic polaratic fourcefeild and lit the little l.e.d.???

****[size=3]For reference only from: **[size=1]
Electrical Inspection Code for
Existing Dwellings

*4.9.7 **Receptacle wiring shall comply with 4.9.7(A) through 4.9.7©.
(A) Receptacles shall have correct wiring when tested with a listed receptacle tester. The tester shall provide indications when branch circuit conductors are not connected to the intended terminals on the receptacle.

**(B) **Where receptacles and branch-circuit conductors are identified for polarization, receptacles shall be correctly polarized.

**© **All grounding-type receptacles shall be grounded or shall have ground-fault circuit-interrupter protection where installed on a circuit that does not have an equipment grounding conductor.
4.9.8 [size=3]Receptacles that fail a blade retention test, with a listed retention tester, shall be replaced.[/size]

**[size=3]*A.4.9.7 [/size][FONT=Arial][size=3]Additional protection can be provided for nongrounding type receptacles by replacing the devices with a ground-fault circuit interruper-type receptacle or a grounding-type receptacle in accordance with 406.3(D)(3)(b) or © of NFPA 70, 2005 edition.
[size=3]Note by this writer: Changing “shall” to “should” would be a good recommendation by a home inspector. This information could become a part of the NACHI SOP and would enhance the position of the Home Inspector. [/size]
[size=3]I carry a tester of this type, it is a good investment!


The outlet is wired for 240 volts. A 120 volt type outlet with 2 hots and a ground (240 volts) will light up all three lights of a three light tester. You should definitely call this out.

Sometimes I see this in some one’s shop where they have reconfigured their table saw for 240 volts. A lot of motors can be wired for either 120 volts or 240 volts. You just have to swap some wire terminals in the motor. Because the saw has a standard 120 volt plug, they just run 240 volts to a 120 volt outlet rather than install the correct plug/outlet configuration. If they are smart, they will label it “240 volts” so somebody doesn’t accidentally plug in a 120 volt appliance and ruin it.


You are absolutely right as far as the standards go. Our company policy here is, if we can reduce our liability without taking on any or much liability, and accommodate a better inspection then we will do it.

While we exceed the standards, we never market this either, as there is no standard to adopt over and above the normal standards. Those inspection companies that market themselves as “exceeding the standards” will have a hard time defending this in court.

Our experience with using amp meters has been nothing but positive from a liability management perspective. We are only responsible for what is accessible, operable and present at the time of the inspection. The problem is, defending this, particularly when it comes to mechanical systems. Most companies will deny the claim without any or much validating data and lose a perfectly good business relationship as a result.

If we can record any test result, we will always do so. This removes the he said-she said later. This also correlates with the requirements of the purchase and sale contract.

For example, when you get the call that the air conditioner is not working after move in, a better defense is one with better testing. To be able to confirm categorically in writing to your client not just the delta T, but also the amperage draw of the compressor at the time of inspection, relieves any and all liability for the claim. The system was operable when you were there and you did everything possible for your client at that time also.

For example a 2 ton unit will run at about 6-8 amps, 3 ton 10-12 amps etc. Our inspectors know the standard ranges of electrical draw for various HVAC systems. Knowing the ranges of electrical draw also enable the inspectors to make more accurate judgment calls.

There are many systems that an amp meter can be used on to help with your liability management. Sewer ejector pumps, depending on size will run at about 7.5 amps, 4500 watt water heater elements will run at about 17.9 amps, 5 KW heat strips will run at about 21 amps, 4 KW Heat strips will run at about 16 amps, portable hot tub heaters will run at about 19.9 amps etc. etc. Again its all about frame of reference. When you do enough testing of electrical systems you will know when you have a bad one. The results will show.

I am not saying that everyone should do this especially if they are not comfortable with it. For us it has helped our company defend claims and qualify the level of our service and inspection on many occasions. The time it takes to take the tests in also negligible.

It’s a business decision.



I use a sperry gfci tester. I have found too many times when the gcfi does not trip if it has two white buttons (T&R) vs a gfci outlet with red.black buttons. I have seen other testers trip the w/w receptacle and have always wondered if its my device or if the other gfci tester is more advanced?

Any help would be appreciated.


An excellent post, and for you, a prudent business decision. I do check the amperage draw on AC units. I also use an infared thermometer when looking at the an electrical panel. It takes a couple of minutes (maybe), but could save someone’s life. I follow-up with an amp probe where one is a lot hotter than the next. Again, for me, its a good thing to do, and my clients believe (and they’re right) that I care about their safety.

It does exceed the SOP, though, and I also do not advertise it, or even report it unless I see a problem.