Quick Grounding Test?

[jrsims58]

My question is how to quickly test with a multimeter if the systems are properly grounded and/or bonded. Such as the panelboard, A/C sub, the ground at the meter, and pipe bonding. As a home inspector I need to know when to recommend that a licensed electrician evaluate further. It is out of my scope to test for fall of potential. I have had several classes on grounding and bounding to include Mike?s. There has not been any method described in this type of rudimentary form of testing. I am looking for a simple, fast, and SAFE way to perform this test, so I can move on or recommend that a professional be called in.

I figure you guys might throw rocks or pliers at me in a room so this seems to be a safer way of asking. If you know of a website that can help, I have been to a bunch, still with out a layman?s answer. Testing like mentioned in 230.95 requires disconnections to be made and it really is for initial installs. 250.56 provides some of the data I?m looking for but refers me to 250.52(a)(2) through (a)(7) then I left scratching my head. I have had people recommend a megger det20c that cost $1,500.00+. I really need some one to provide a few simple test so I can say yes it is a grounded system or have an electrician take a look as it does not measure up to a minimum standard of some sort.

Do you simply touch a probe to the meter casing and the other to the ground or open the jaws and place around the ground wire at the rod?

Your help would be appreciated.

 

[Pierre C Belarge]

jrsims58
It is good to see that a HI is trying to do the right thing. I will say that the testing you are trying to perform is not left in simple steps as you are hoping for, as there is no simple procedure. Without the experience of wiring and testing over years, you are likely to make mistakes you are not even aware of. My advice to you is to not test at all, but use your two best tools:
1. your brain
2. your eyes

With those two tools, you can see most situations that may be suspect, and then refer it to the electrician.

Remember that testing at panels take the proper training and PPE.

 

[brian john]

Pierre:

Basically summed it up, testing a grounding system involves expensive test equipment (depnding on your def of expensive) and it best requires some expierence and understanding.

In a resisdence, testing is seldom completed, as mentioned common sense and expierence go a long way to visually inspecting the system.

There is a ton of literature available regarding this issue, from basic to very involved, but IMO the Mike Holt stuff and Soares Grounding book are the basic literature you should use for reference.

If you have a specific issues post here or fell free to IM me, I would rather answer someones question then have them unsure of themselves.

 

[tom baker]

I would use a volt stick such as the Fluke Volt Alert. There is a version that Con Ed is using to test for energized manhole covers, etc, that will go as low as 5 volts.

 

[petersonra]

My question is how to quickly test with a multimeter if the systems are properly grounded and/or bonded. Such as the panelboard, A/C sub, the ground at the meter, and pipe bonding. As a home inspector I need to know when to recommend that a licensed electrician evaluate further.

I do not know of any cheap way to test these things.

I would not worry a whole lot about whether you have a "good" connection to ground or not. If a visual inspection shows an undamaged green wire of the right size is properly connected to the grounding electrode(s) I think that is adequate.

Bonding might be a little different, but again, just a visual inspection goes a long way.

I am not sure the average electrician, licensed or not, would do much more.

 

[George Stolz]

I figure you guys might throw rocks or pliers at me in a room so this seems to be a safer way of asking.

Where's the trust?

It is out of my scope to test for fall of potential.

I would not waste any time testing the grounding system. Check to see that the grounding electrodes are connected, and call it a day. The NEC does not even require a fall of potential test to speak of, so I doubt anyone would expect you to.

I would make bonding your primary concern of the two.

The Ideal Shure-Test is a $200 tester that has a three-pin plug on it (for plugging into receptacles). They claim it can find a "bootleg ground", which is a term for the practice of using the neutral at the receptacle for a connection to the grounding terminal of the receptacle. I do not own one, so I can't vouch for it, but they are fairly popular.

Technically, a "properly bonded" system can't be tested, IMO. The only way I know for certain that the bonding is code compliant is to see it visually. Just because a lamp on a tester lights does not necessarily mean that the conductor it's checking is properly sized or installed correctly.

If you pull out a handful of receptacles to determine the wiring method, and then plug-check the whole house, I would say that's about all I would expect from you, IMO.

As for lights, Tom's idea of the tick-tracer might be just the thing. An unbonded fixture has a higher probability of inducing a voltage onto the fixture itself. As soon as the fixture is bonded, a tick tracer will not light, until you have it inside the lamp-socket itself, for the most part.

 

[Bea]

I agree with George


I would not waste any time testing the grounding system. Check to see that the grounding electrodes are connected, and call it a day.

Look in panel to see if there is a grounding eletrode conductor that would connect to a ground rod or rods. Then also see if there is a bonding jumper or grounding electrode conductor to water line if its metallic and be done with it

 

[jrsims58]

Thanks for tour comments

Thanks for tour comments

Gentlemen,

I thank each of you for the response to my questions. I have researched the topic through a number of sources and determined that I can only state if there is a ground or not, with a clause it may or may not be of the proper size check with an electrician to be sure next time you have one on site.

George, the sure-testers do seem to work and I do own one, they are 250-350 depending on if you want AFCI to go along with the GFCI tester.

I do visually check for both grounds and bonding. Here in Atlanta most of the homes I do are pre-70s I work in town. So I get a lot of old or remodeled structures.

I do have a tic-tester bought it after I hurt my elbow. I tested the panel with the back of my hand and got hit! Someone had used sheet metal and drywall screws to attach the panel cover, in doing so they pierced a wire and energized the cover. I only looked at the screw heads there and went no further in, and put a danger sticker above and insisted they call an Electrician. I do like the advise on checking the lights with that device, I?ll have to runs some test on known issues and some I know are right, to see how it performs.

Thanks for all the advice so far. If there are any issues where you are called in by a HI and it?s not one, please let me know. I do not wish to waste anyone?s time mine, yours, or the client?s. I do not wish to be an expert but I do have to know and understand the basics of all the trades. I would be happy to share that information with the 9,500+ HI in my association.

The reason for the questions I see all the time where a ground is connected to an abandoned galvanized pipe, or a copper pipe with no jumper across the pressure regulator, or copper pipe that attaches to a plastic feed just inside the foundation. In all these cases it is not a grounded system.

Regards to all,