I keep getting bad ground on every receptacle in the house. Is there a way to test without using this little device...like a multimeter? I turned the breaker off on the receptacle I think that was causing the bad ground but still every outlet in the house still shows bad ground.
On a 120 volt circuit only the hot (black) is connected to a circuit breaker. The neutral and grounds remain connected even when the breaker is in the off position so that won't change your ground situation.
I removed the outlet and just capped the wires and I still receive bad ground. This house was built in 1995. Yes, I checked the outlet by the panel and it still shows bad ground. And yes, I do have a multimeter.
Charlie2 - That tester is going to display a 'bad (open) ground' if it detects resistance of the ground to be greater than ~10 Ohms.
If you wish, you can dig into learning about what resistance establishes a 'good ground' and how a good ground is actually achieved. It would take me far too many words and way too much time...
Also, the last receptacle in a downstream feed run will likely have the highest resistance and will be more susceptible to fail the acceptability resistance threshold of the tester.
At that age everything should be grounded. At this point I'd open the panel and inspect. Keep in mind that the some parts inside the panel are hot/energized even with the main breaker is off. Look for anything obvious like the main ground wire disconnected. I would also go outside and inspect your ground rod and the wire connected to it. They are usually outside near where power enters the home or near the panel. It is easy for someone mowing to break the wire or knock it loose from the grounding rods.
I'd suggest an inexpensive analog multimeter. It will help determine if the ground is problematic or completely disconnected. Or possibly, the plug-in tester may have an issue.
I personally use a neon tester way more often, it's easy to check for power/neutral/ground, but in your case where you may have a connected but sub-par ground, a multimeter might be a better choice.
The little unit that I used says "bad ground", is that the same thing as open ground or no ground?
I'd guess a 'bad ground' indicator on that device would mean either a ground with greater than ~10 Ohms resistance or no ground at all.
I wouldn't put too much trust or confidence in that device - about as much as I believe in the Earth being flat.
It would probably end up in the trash if it was mine or given to a friend as a prank so he can worry about his house wiring having a (wait for it)- bad ground!
I have not opened the panel to check for the ground yet but I did check the ground wire outside and everything looks normal. I use my multimeter to measure the receptacle I was working on and it seemed to be normal as well. Then I measured the hot and ground for voltage and it comes close to 120v. I tested continuity of the ground and the plate screw and there is continuity there. Next, I tested the ground and neutral and I got continuity as well. I just don't get why every outlet in the house is showing bad ground.
Charlie2 - I've already provided you the reason why 'every outlet in [your] house is showing a bad ground' on that wonderful, precision instrument you are using to test your electrical ground integrity.
► That tester of yours is going to display a 'bad (open) ground' if it detects resistance of the ground to be greater than ~10 Ohms.
According to the National Electrical Code - Section 250, a ground system should have a grounding resistance of 25 ohms or less. So, Charlie - that Gardner-Bender Sperry Instruments tester of yours will show a 'bad ground ' threshold far more stringent than even the NEC suggests you should have!
According to NEC Section 250.53(A)(2), a single rod, pipe, or plate electrodes needs to be supplemented with an additional electrode unless it can be proven that a single rod, pipe, or plate grounding electrode has a resistance to earth of 25 ohms or less.
Don't be confused by thinking that 25 Ohms resistance is more stringent than 10 Ohms resistance because 25 is a larger number than 10. It's important to know that 10 Ohms is a more stringent value than 25 Ohms.
Chances are almost certain that your ground resistance is 25 Ohm or less and perfectly okay.
You see, a 10 Ohms resistance is way too low of a value - it is not necessary - it's too stringent! Only 25 Ohms is necessary, yet that Gardner-Bender Sperry Instruments tester of yours is factory set at a 10 Ohms (to pass) the ground measuring threshold - - so of course it's going to display 'bad ground'!
In other words, the tester is requiring 10 Ohms of resistance to pass as a 'good ground' whereas the NEC only suggests only having 25 Ohms or resistance. The tester is making it more difficult to pass than the NEC says you should have!
I recommend that you return that tester back to Home Depot or wherever you purchased it for a credit, or throw it out with the trash!
In case you want proof the tester is factory set at 10 Ohms before grounding passes - just take a look at the image below where I circled it in red.
Last edited by Kooter; 08-24-23 at 02:27 PM.
Reason: orthography
Thank you for the explanation, much appreciated! Okay, so there must be a way to use my multimeter to measure the resistance in Ohms, right? I found this article on How to Measure Ground Resistance With a Multimeter but I'm not sure how valid it is. If there is a YouTube video showing how to measure ground resistance with a multimeter, it would be much preferable.
Charlie2 - Without a clamp-on ammeter or a megger you're out of luck to easily measure the resistance of your residential electrical Earth ground. Because to accomplish a measurement otherwise would require that you do the following which I really do not think you want to do, nor do I recommend you even consider doing it:
This is NOT to be done!!!
Essentially you would have to disconnect your electrical system's connection to the Earth-driven ground rod that provides your electrical service's protective grounding so that you could connect probes to that Earth-driven ground rod as well as to another electrode (ground rod) driven into the Earth to make or form a crude circuit of sorts in which [then] a known voltage could be induced into this circuit for a measurement to be made of the resistance (or integrity value) of the Earth ground you're measuring, given that V÷ I=R or induced voltage divided by its current equals resistance.
As I said; you're out of luck to easily measure the resistance of your residential electrical Earth ground !
You can rest assured that the Earth ground resistance provided for your electrical service is more than adequate and has met the standards of your PoCo and your local electrical inspection authority - as long as the ground wire (almost certainly to be a #6 solid copper wire) from your electrical service is still connected to the Earth-driven ground rod nearby your utility's watthour meter socket. Moreover, as long as this grounding is still properly connected to your electrical service [then] it is providing your electrical service an adequate ground.
Lastly, that Gardner-Bender Sperry Instruments tester of yours is worthless for testing the ground integrity of your electrical service for the lengthy reason I have already wasted far too much time explaining. That tester deserves to be given a resting place in the bottom of your trash can!
Last edited by Kooter; 08-25-23 at 11:23 AM.
Reason: orthography
I saw this tester on Amazon. I assumed it's better than mine Sperry?
Charlie2 - The Klein tester is identified as a 'GFCI Outlet Tester'. The specifications do not state that it actually tests the ground, however the tester does use the ground to intentionally trip the GFCI outlet device and actually shows the amount of time it takes to trip.
Do you a recommendation on a good tester then? Thanks!
Charlie2 - Yeah, I would have placed a huge bet you wouldn't do that procedure!
All those cheap little testers are about the same. There's not one that is really any better than another.
Maybe you should consider having an inexpensive clamp-on multimeter that also takes probes. It's not going to test your GFCI outlets, but maybe you'll find it useful to have.
Any coffee shops near you that still supply outlets for laptop charging? I guess those are disappearing now. But if there was one close by, maybe you could plug your tester in one of their outlets. I don’t see any harm in that and maybe it would tell you something, especially if the suspense is really bothering you.
Or could one of your neighbors plug it into one of their outlets for a test?
I am an electrical ignoramus; however, I do understand the 10-25 argument. The only thing is though, I thought that a good ground is supposed to be about 5, and some are even lower. So, your current tester, could, I guess, be justified in calling something above 10 …”Bad”.
I don’t see how you can assume the odds are that the current resistance is between 10 and 25. As pointed out by Zorfdt in post #9, the tester may be just plain broken or maybe you have no ground at all.
If it’s a known fact that many homes are somewhere between 10 and 25 then … my bad!
zoesdad thanks for the input. I will try to use the tester on my brother's house some time tomorrow and see what it shows. I'm guessing that it will be green. I know that I've tested my house with this tester before and it was green. I did use my multimeter to test the ground and hot and it does show 120v so I'm assuming I do have a ground wire?
I did use my multimeter to test the ground and hot and it does show 120v so I'm assuming I do have a ground wire?
That's right you did say that in a previous post - my bad. I forgot. ( I just went to Home Depot to get some things. Wrote myself a list so I wouldn't forget something. Forgot to check the list and missed something -lol)
Good? What is 'good'? I guess 'good' needs to be defined
Forget no resistance, which is perfect. Forget attempting to establish an Earth ground resistance of 5 ohms because it is really unrealistic. And, 10 ohms in most cases is extremely difficult to achieve without an elaborate grounding 'system'.
Obviously it is totally impractical for The National Electrical Code to impose the expense, the time and the labor needed to install an elaborate ground system for typical industrial, commercial and residential electric services that would likely require at minimum; multiple oversized diameter, sectional/threaded copper-clad ground electrodes, spaced 10' to 20' apart and driven deeply into moist soil to achieve the low resistance values you thought is 'good'. So what does The National Electrical Code (NEC) say about ground resistance?
It should be noted that The National Electrical Code (NEC) does not dictate anything remotely close to those low ground resistance values you've read about on the Internet!
Here's what the NEC establishes as good and reasonable:
The National Electrical Code (NEC) section 250-56 establishes a requirement for a single ground rod or ground plate to have an earth resistance of 25 ohms or less.
That tester uses the word “Bad” right on its face, which I think would obviously translate to “Not Good”, so I would want to know from the test instrument’s viewpoint, what “Good” would therefore mean? Obviously, it would mean less than 10. Does that jibe at all with information from many sources that associate the word “Good” with the value 5 - yes it does.
However, if most homes don’t achieve a value anywhere near less than 10, then yes, the tester is a bad piece of equipment that will mislead many or most homeowners. In fact, I did find one of their promotional videos (can’t find it again just now) where they stated that the instrument does ground testing “for the required lower resistance 10 ohms”. The term “required lower resistance” caught my attention, especially the word lower. So maybe it is in fact buyer beware, and you have to know that you’re testing for unusually low resistance with that device. Maybe that is in fact the wrong device for the average home.
However, I don’t know of a place where statistics are compiled with information on the actual values measured in most homes.
It sounds like you are very sure that a better instrument will measure a value more than 10, but less than the NEC allowed maximum of 25 and thus the problem will disappear. I don’t see how you isolated it to that range.
...a better instrument will measure a value more than 10, but less than the NEC allowed maximum of 25 and thus the problem will disappear. I don’t see how you isolated it to that range.
I don't think any simple and affordable device will ever be made available that measures the integrity of Earth ground with a value threshold range that would trigger a 'Bad' result at a value higher than 25 Ohms and a 'Good' result at a value of 25 Ohms or less.
The ability to achieve a resistance value of 25 Ohms or less varies widely across the country based on the type or composition of soil/ sand/gravel/rock and moisture content. Some areas will require more than one ground rod and will need two ground rods. Some installers will elect to go with a Ufer ground. The goal is 25 Ohms or less.
No doubt there are a gazillion electric service grounds that have never even been tested by an authority or tested and did not meet the NEC 25 Ohm requirement - - or maybe once met the minimum requirement, but no longer does for whatever reason. And then, of course there are a ginormous number of electric service grounds that are comprised of an inauspicious 6 foot 5/8" galvanized ground rod that was purposely cut in half and 3' of it is driven at a very shallow horizontal angle just underneath the surface of the ground and bent enough to attach an acorn fitting for the #6 bare copper ground wire so it visually looks like an appropriately driven 6 foot ground rod...but it probably measures out at 5k Ohms or higher.
Last edited by Kooter; 08-26-23 at 03:33 PM.
Reason: orthography
Not sure if this has been covered entirely, but Dane suggested in an early post "I would also go outside and inspect your ground rod and the wire connected to it."
To that I would add...For that year house, the ground wire from the panel should go to ground rod(s), but also the cold water main. On some houses they cheated and only ran ground to the water main. I would check to see if the ground was detached there.
I have not seen or used the GB tester that the OP posted. All I can say is everybody in the trade uses the three light testers. I am skeptical how that tester can accurately measure a 10-ohm resistance between any two points.
The ground is not derived by the ground rod or the water pipe ground, it is derived at the transformer by the grounded conductor (Neutral). This is why the equipment ground wires and the neutral wires are connected to the same bus in the main panel.
A ground rod is only to provide a low impedance path to the earth for high surge events. The NEC requires a ground rod to have a resistance of 25 ohms or less. If it does not then you are required to install another rod at least 6' apart. If that rod or group of rods still has a resistance greater than 25 ohms you are not required to do anything more. This is why the rod is not your primary grounding electrode.
I am skeptical how that tester can accurately measure a 10-ohm resistance between any two points.
Tolyn Ironhand - I agree! The plug-in tester is unable to measure the resistance of anything because I do not think it has any circuitry capable of doing it.
I was able to find what a Sperry Instruments representative said about this particular circuit test being discussed when asked by someone else about its ability to test the integrity of Earth ground. I find this interesting!
The Sperry Instruments representative said; "The tester tests 7 common wiring conditions. The tester is testing the immediate ground connected to the socket that it is plugged into. If the ground resistance is greater than 10 ohms, this unit will illuminate a red indicator light to warn of a bad ground ‘at the outlet’.It is not designed to test the ground rod, just the ground at the outlet it is testing. Sometimes there isn’t even a ground at all."
The Sperry Instruments representative vaguely suggests that the tester has circuitry needed to measure a comparative resistance (i.e. the 10 ohm value), which I highly question - but apparently only the ground resistance at the socket (outlet), which is presumed to be measured right at the outlet's ground and neutral jaws inside the outlet's plug-in holes. I'm still highly doubtful and not convinced at all the Sperry plug-in tester can measure, sense or compare the resistance of anything at all!
Nevertheless, this leads me to wonder if Charlie2 has a subpanel with only a 3-wire feed from a main panel and no EGC for the subpanel. If this is the case - and he does have a subpanel with only a 3-wire feed from the main panel then he needs to bond the neutral and ground at the subpanel, which is okay under older code. Otherwise, he needs to have a dedicated EGC for the subpanel.
3-wire to a subpanel is a violation of recent code. It used to be permitted for new installations which may apply to the OP (if he does happen to have a subpanel). Pre-existing is still perfectly okay under recent codes. Recent code however requires 4 wires (L1, L2, N plus EGC).
Four (4) wires are needed to the sub panel under more recent code, then the neutrals and equipment grounding conductor are separated and the grounding electrode conductor gets connected to the subpanel's equipment grounding conductor bar. I wonder if maybe the OP may be using the grounding electrode conductor at the main panel as a ground, which if not bonded at the subpanel (if he even has a subpanel) may indeed give the 'bad ground' result he gets on all his outlets.
If there are only 3 wires he needs to bond the neutral to the can and the grounding electrode conductor and equipment grounding conductor get connected on the neutral bar also - just as it would be done at the main panel for a new service.
Lastly, as for the GFCI protection is offers - good ground fault protection system has very little, if anything, to do with having a good Earth ground. Ground fault protection from GFCI devices do not even need a ground to interrupt the circuit...it senses 5mA or greater imbalance between the line and the neutral.
The GFCI test button internally puts a 24k ohm resistor across the line and neutral to impose exactly a 5mA imbalanced current draw to purposely trip the mechanism and interrupt the circuit at the outlet. 120V÷.005A= 24,000 ohms. No ground whatsoever is needed or used by the GFCI device to trip as required at 5mA or to test it by pushing the 'Test' button...
Last edited by Kooter; 08-27-23 at 02:53 PM.
Reason: orthography
Charlie2 - I hope you're following your 'Bad Ground' thread because I've got news for you!
The Sperry Instruments #HGT6520 Receptacle Tester did not pass a review test because (wait for it) after pressing the black button that reads 'PRESS FOR GFCI TEST' it displayed 'BAD GROUND' (see image below when it was actually being tested) and it continued to display 'BAD GROUND' with all the future testing.
This Sperry Instruments #HGT6520 test device was tested by an expert with an absolute known good electrical grounding system.
Clearly this device is pure junk! Because of this find I made I'd say the chances you have anything wrong or defective with your grounding is pretty much zero I am happy to report...
The Stop Shock II Circuit Analyzer makes it easy to test GFCI receptacles and determine the appropriate wiring correction needed.
This GFCI tester uses advanced circuitry and a patent-pending proprietary design to precisely detect the required low resistance (less than 10ohms) on ground wire and provides a clear and easy-to understand single LED readout indication for correct wiring or Bad Ground, Open Neutral, Hot/GND Reverse, Hot/NEU Reverse and Open Hot wiring errors without the need to memorize or decipher a dual-indication chart
I know we are beating this to death but I think this is relevant. It looks like your (and others) skepticism is justified. Notice that they describe “a patent-pending proprietary design” detector. Obviously, they had to put some work into that problem. So how good is their solution really? Maybe they really succeeded – but maybe not.
They use the term “required low resistance”. I would think that most average home owners, including me, with general reading skills, would think “required low resistance” in their description above means it is a general requirement, that is, “required” means “required for everyone”. I don’t see how you could nuance the words in that particular context above to mean anything else.
However, it looks like “required” is just flat out wrong. They should have used the word “recommended” since the NFPA and IEC both only “recommend” < 10 ohms, and so maybe that’s what they are referring to, but twisting that to mean “required”. Who knows!
Maybe it’s just a case of weasel words gone too far.
Charlie2 - You may be interested in reading the following review made by a home inspector of the Sperry Instruments #HGT6520 Circuit Tester like you own and have had trouble with:
0.0 out of 5 stars - Falsely indicates “BAD GROUND”
Style: Sperry HGT6520 GFCI Circuit Tester
I had high hopes for this outlet tester, based on the numerous positive reviews on Amazon.
Unfortunately, I was extremely disappointed with its performance.
The problems that I have identified:
1) It trips GFCI breakers when inserted into the outlet, without touching the test pushbutton. Not always, but most of the time.
2) It indicates “BAD GROUND” for (at least some) known good outlets /circuits. I verified this on a brand new circuit which I had installed (homerun to my electrical panel), using 12/2 with ground Nonmetallic wire (Romex). I was meticulous with all terminations and splices. One of the (brand new commercial grade) outlets which indicated BAD GROUND was only 2 feet from the panel, with a wiring run of about 6 feet, and only one splice between the panel and the outlet. So I decided to do a “seat of the pants” test: I shut the power off to the panel, removed the panel cover, and did an end-to-end resistance check from the ground slot of the “bad” outlet to the other end of the equipment grounding conductor where it terminates on the panel ground bus. The result? Less than 0.1 ohm, according to my Fluke 117 digital multimeter (meter resolution is 0.1 ohm, and it did not even register any resistance above that of the test leads). My other meters gave similar results. This is far far lower than the 7 ohms or 10 ohms resistance that should trigger a “BAD GROUND” reading on the outlet tester. (Sperry's website says 7 ohms in the operating instructions, and 10 ohms in the product overview—which is it, Sperry?).
Yes I know that there is a difference between DC resistance and AC impedance, but these differences are very small for small conductors, and certainly nowhere near enough to explain a “BAD GROUND" reading.
Note that this tester indicated “correct” for some of the circuits on my house, and “BAD GROUND” for others. However, based on my experiment above, I know not to trust a “BAD GROUND” reading with this tester. Other testers have indicated “correct” for all these circuits (including two other testers which also test for low ground resistance).
The previous version of the tester (the HGT6120), sold under the Commercial Electric brand name at a popular big orange home improvement store, has received very poor reviews for this very same issue - falsely indicating "BAD GROUND". It appears that this new version (#HGT6520) suffers from the same problem.
For the above reasons, I would NOT recommend this tester to anybody, and ESPECIALLY not to home inspectors.
[This review was made on Amazon.com for the product]
The sub panel next to the main panel needs to have the grounds removed from their current location and a new ground bar needs to be installed. The two neutral bars "float" and are currently correct. The wires that are feeding this sub panel do not need to be on the two pole 40 amp breaker assuming that they are already protected by a proper breaker in the main panel. They can backfeed into the 100 amp breaker that is not being used. That 100 amp breaker will only act as a disconnect.
Assuming that the garage is attached to the house, the garage sub panel also needs to have the grounds removed from their current location and a new ground bar needs to be installed. The two neutral bars "float" and are currently correct. The feeder wires can be connected to the main lugs at the top of the panel instead of the two pole 60 amp breaker assuming that a proper breaker protects the cable in the main panel. If you want to keep the two pole 60 as a disconnect then I would recommend installing a hold-down kit.
I'm confused why in the house sub panel the 60/2 C/B (without a hold-down screw BTW) is being used as a back-fed main breaker instead of the 100/2 factory installed (I presume) main breaker (with a hold-down screw already installed). I realize having a panel with 100 amp bus and M/B doesn't oblige you to run 100 amp feeder, but I don't understand not using the 100 M/B and feeding it from the main panel apparently just a few feet away.
In the garage sub panel - why use a 60/2 as a back-fed main breaker (without a hold-down screw BTW) instead of feeding the MLO panel at the lugs from a C/B in the main panel or the house sub panel?
I wonder if this installation is a 'work in progress' that is still being addressed and just partially completed at this stage.
Tolyn Ironhand - I'm glad you covered the grounds. I knew you would!
Last edited by Kooter; 08-31-23 at 05:17 PM.
Reason: orthography
In the garage sub panel - why use a 60/2 as a back-fed main breaker (without a hold-down screw BTW) instead of feeding the MLO panel at the lugs from a C/B in the main panel or the house sub panel
The only reason you would need the breaker would be if the garage is a separate building. If that were the case you would also need a ground rod.
I'm confused why in the house sub panel the 60/2 C/B (without a hold-down screw BTW) is being used as a back-fed main breaker instead of the 100/2 factory installed
The only reason would be if you are running a tap conductor off a larger conductor/circuit. This is rarely done in a dwelling.
Tolyn Ironhand - By looking at the two sub panels Charlie2 has shared pictures of (above), do you find any reason why that Sperry circuit tester may have thrown a 'Bad Ground' result?
maybe a misstatement of the title... connecting blk to blk and wht to wht doesn't work.
I've had an outside light working for years controlled by an indoor switch. I put on some siding, and now the light doesn't work... well it works if I attach the black(fm light) to black and white(fm light) to ground... Test meter shows 124v from black to ground in jct box, and only 92v black to white.Read More
I have 2 baseboard heaters in my garage about 10 ft apart joined by conduit. See pic.
They started the first heater conduit/wire in from the left end, then tried to tape/hide the wires up and out of the way en route to the right end, which goes out to the conduit joining the second heater.
As you can see the wires are now dangling. (They are either #12 or #10) I know this isn't Kosher, and will get flagged one day when we sell the place.
My idea would be to disconnect the wires on the right side and get them into MC flex conduit and appropriate transition couplings .How does this sound for a start? Or what should I do?
[img]https://cimg4.ibsrv.net/gimg/www.doityourselft.com-vbulletin/2000x1504/20230917_184846_505bd27355f12701b2f3c9ad8674e6be5b5694d6.jpg[/img]
[i]Left Side Wiring Start[/i]
[img]https://cimg7.ibsrv.net/gimg/www.doityourselft.com-vbulletin/2000x1504/20230917_184955_4aa22041d1feb0ce6180fc20ec5891a389a6fb10.jpg[/img]
[i]Wire Junction to Right Side, then to out to conduit and Second Heater[/i]Read More
08-23-23, 06:13 PM
