excavating and found … ?grounding rod?
I’m kind of stumped as to what to do and thought I would ask you guys. I am excavating a trench around the foundation of my house in order to install some drainage tile, and I came across what looks like a grounding pole. The city came by and marked where everything underground resides around our home, and nothing was marked where I found this thing. It is near where our electricity enters the house, but I see nothing exiting our house to connect to this pole. It is a very thin pole, maybe a quarter inch in diameter. Our electrical service is mostly pretty old, 56 years to be exact, and I had always thought it was probably grounded to our metal water line. However, a small subpanel was installed years ago prior to our owning the home, right next to the old panel, so maybe this is a grounding rod for that newer panel. I don’t know. It seems kind of thin to be a grounding pole, but I don’t know what else it could be. It is also several feet away from a central air conditioner.
I am a competent DIY but have very little experience with electrical matters. I plan on digging elsewhere until I find out if it is safe to continue digging around this thing I found. I inadvertently touched it with my shovel before I knew it was there and didn’t get shocked but don’t feel comfortable continuing until I know more about what it is. Can any of you tell me? And what should I do? Thanks for your help.
Replies
Could it have been the grounding rod for a lightning rod ?
A person with no sense of humor about themselves, has no sense at all.
1/4" dia and not connected to anything... left over construction trash or an abandoned temp grounding rod...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
Forget the primal scream, just ROAR!!!
They city did the marking or was it by a constorium hired by the member companies. The reason that I ask is that there are other items than what the city supplies. Telephone and cable besides gas and electric which are also private in most places.
Anyway they only mark for services for organization that hire them.
I live in a very small city that does not belong and when I underground utilites marked they could not mark for the water and sewer.
In any cases they don't mark for homeowner equipment or lines. If that was a ground rod it they would not have marked it.
I am not sure of what was done back them, but the water line might have been the only ground.
Current code allows use of the water pipe as a ground (if in direct contact with the earth for at least 10 ft and the connections are made within 5 ft of it entering the house). But it also requires a secondardy ground electrode, usually a ground rod.
And ground rods are required to 1/2 if nonferrous or 5/8 is steel.
If it was a ground rod there should be connection to it at the top or within a few inches.
You can also look at the main panel and sub-panel and see how many grounding wires there are and where they go.
As you describe it I am guessing that either it was a ground rod at one time and since abandoned or that it was used as a somekind of reference for a string line or the like.
Thanks for responding Bill. The way it works here is that i call a central number, and that place contacts all of the individual utilities to come out and mark their stuff. I address some of the other things you mention at the end of this thread where I respond to everyone.
AL
It is likely an old grounding rod that was abandoned, or perhaps disconnected by some prior resident who found that the wire got in the way. It should be electrically harmless -- if there's any "juice" on the thing then you have a MAJOR problem. I personally wouldn't worry about digging around it from an electrical point of view (but do definitely stick an old tennis ball or some such on top -- rods like this are VERY dangerous in construction sites from the standpoint of falling on them).
Do double-check, though, that the electrical connection isn't farther down on the rod -- you need to go down about a foot to be sure there's no wire on it. If there is a connection then it should be preserved (or replaced, with a rod elsewhere) to assure the integrity of the grounding system.
The thing is likely about 5 feet long.
Current code requires the use of a grounding rod in many/most cases, in addition to using water pipes. It has been found that a single ground connection is unreliable, so a "grounding system" of 2-3 elements is now required. But your system was probably put together before this requirement.
I'm putting a new ground rod in after excavating around my house. I'm having a heck of a time pounding the thing in. All the backfill around my house is rock. I got about 4' pounded in and don't know if I can get it in any further. How much needs to be burried is my real question?
Thanks,
John
You need eight foot in contact with the earth. Not necessarily driven down vertically. Angle it to miss the rock or lay it horizontally down above the rock layer.
I bury at least ten feet.
Use a post driver to drive it in. Mine gets it to where only a foot or so is left, and a sledge finishes the job.
Here is the tool I am talking about.
I got mine at the local Del's Farm Supply store for ~$16.00
Post driver
A person with no sense of humor about themselves, has no sense at all.
I'm using 1" type K copper pipe for ground rods, sinking them hydraulically to 30 ft. All it takes is a garden hose and a little rigging to hold the pipe up. I put together the 30 ft. of pipe, hammer the bottom end mostly flat to make a nozzle, and put a 3/4" NPT fitting on top to attach the hose. Stand it up, and let the water run for 4 - 6 hours. Rocks up to about grapefruit size will cause it to stall for a while, but eventually it erodes out around the rock and pushes it aside. A friend of mine used to do ground rods for TV transmitters this way, but he went as much as 45 - 60 ft. down.
-- J.S.
Al
Many years ago I installed cable television services into peoples homes. At that time we were required to ground our installs seperately from the power company and we used 4' ground rods about 3/8" in diameter. I think that may be what you discovered.
Victor
Thanks to everyone for the good information. My main electrical panel in the basement is clearly grounded to our plumbing, and there appear to be no ground wires leaving the subpanel. Question: Is it supposed to be grounded separately, or does it get grounded by virtue of being connected to the main panel? This rod outside appears to be copper and looks like some sort of defunct grounding rod. There is nothing connected to it for the first foot or so. It could be a ground for cable like VSkellett mentioned, and maybe no one actually hooked it up--or maybe it got severed at some point a long time back. It's hard to say. Whatever it is, it is something the utility company does not keep track of. For future reference, if you do encounter the actual grounding rod for your electrical system, and you need to dig there, what is the right way to handle it safely? Granted it shouldn't have electricity in it unless you have a problem--but how do you guys handle something like that safely? Do you need to shut off your power, do your digging, replace the rod, then turn power back on? For an old panel that has no actual main shutoff, you essentially accomplish the same thing by just yanking out all of the fuse boxes, right? I really appreciate you guys taking the time to help me out. Thanks.
AL
"appear to be no ground wires leaving the subpanel. Question: Is it supposed to be grounded separately, or does it get grounded by virtue of being connected to the main panel?""GROUND" serves serval purposes. For the inside of the house the Equipment Grounding Conductors serve to provide a path for fault currents and also insure that all "grounded" surfaces are at the same potential level. To accomplish that there shoudl be one point and only one point where all of the equipment grounding coductors come together and tie to the grounding electrode system (ground rods, water pipes and other electrodes). That point is at the service entrance, usually the main panel.So your sub-panel should only have a ground that goes back to the main panel the equipment grounding bus bonded to the metal case and a separate isolated neutral bus. However, note that older sub-panels that a the neutral bus was not separated from the ground bus and single neutral was connected back to the main panel."Whatever it is, it is something the utility company does not keep track of."Ground rods are customer equipment and the thus the utility does not have anything to do with it. While this various from utility to utility typicaly the power company ownes the drop from the pole to the mast and the meter. You own the mast, the wires in the mast, the meter base, ground electrodes, and panel."For future reference, if you do encounter the actual grounding rod for your electrical system, and you need to dig there, what is the right way to handle it safely? Granted it shouldn't have electricity in it unless you have a problem--but how do you guys handle something like that safely? Do you need to shut off your power, do your digging, replace the rod, then turn power back on?"Good question. I not a pro and would be interested in what they say.In the worse cases there might be current going though your ground rods even if the mains where turned off that your house. But that would be an unusal situation and you would probably notice it with flickering lights in the house.I guess one could check with an clamp on amp meter and if that does not show anything to open the connection and measure any voltage difference.However, if you have a dual ground electrode (either 2 rods or rod and water pipe) I don't think that I would be very concerned about disconnecting one as you move it.
A subpanel, when within the same structure as the panel feeding it, is supposed to be grounded via the cable coming from the main panel. In the subpanel the neutral and ground buses should be kept separate -- insulated from each other.If you have to deal with a "live" ground rod, the way to handle it would be to install the new rod (or a temporary replacement), run a new ground wire to that, then disconnect the old rod.When connecting the new rod try to make the last connection at the panel, and when disconnecting the old one try to disconnect the panel connection first, before disconnecting the rod end. While making these panel connections/disconnections it would be wise to disconnect the panel main, or any external disconnect feeding the panel.In the case of installing a temporary rod, it would be OK to splice a new piece of cable onto the existing cable for the existing ground rod, but when installing a permanent rod you should attempt to have a continuous (unspliced) piece of cable running the whole distance.
Bill and Dan, thanks for answering my new questions. This forum is a great resource. I pulled out that rod, which indeed appears to have been some old grounding rod.
The only problem with you guys answering my questions is that now i have to get back to work! Doh! Thanks again.
AL
Good information - but it brings up a question/concern for me.
Northern Virginia home built in 1980, aquired by DW and I in 2000. All electric service in neighborhood is underground. AL type to the main panel. Cable comes up from the ground in conduit into the bottom of the meter box, then back out the bottom with a 90* into the basement where the main panel is located. There does not appear to be a ground rod in use. House has copper plumbing supply lines and the main panel has a ground to the copper via AL cable.
Question(able) is this, the 1" water main feeding the house is plastic.
What is the actual conductor when using the plumbing system as a ground path, the metal or the water?
Me thinks I gots a problem....
Dan
"I will get my basement done, I will get my basement done, I will get........"
Double-check all of the visible ground wires coming off the main panel or the outside meter/disconnect. There may well be one or two ground wires you're not seeing.It's possible that, when the service was buried, they also buried a ground rod or a copper plate, and the connection for that is running through the same conduit as the service entrance. (Note that the conduit you see most likely only goes down a couple of feet into the ground, and then direct burial cable exits from there and runs to the utility's wires.)Also, starting around 1980, it became common to bury a ground wire in the concrete foundation. It turns out, for reasons that I'm not sure are totally understood, a wire encased in concrete makes a better ground than a wire simply buried in earth. Since about that same date, it's not been "legal" to use water pipes as the primary ground, because of plastic pipe, et al.
> Also, starting around 1980, it became common to bury a ground wire in the concrete foundation. It turns out, for reasons that I'm not sure are totally understood, a wire encased in concrete makes a better ground than a wire simply buried in earth.
This is called a Ufer ground, named after the guy who invented it. Usually it's done by connecting all the rebar together and using that as the ground. Mr. Ufer was in the military, and devised this back during WWII to protect munitions bunkers.
-- J.S.
If you put plastic under the cement to stop water from coming up from the soil, does using the cement for a ground still work?
You're never going to be successful at creating a complete membrane under the concrete, and, in particular, you don't (normally) put plastic under footings, where the Ufer ground will be.
I'd think it would really hurt the effectiveness of a Ufer. Of course you'd get a few little holes in the plastic, but for the vast majority of the area what you've created is a big capacitor. Grounding thru that would work better as frequency goes up, so it might not be so bad for UHF TV transmitters. But they tend to sink really big copper pipe rods for those.
If you need Ufer grounding, it would be smarter to not have plastic between the concrete and the dirt. You could wrap the wood in plastic, and remove it when you strip the forms.
-- J.S.
Dan, you'll get more and better answers if you start your own thread.=0)
A person with no sense of humor about themselves, has no sense at all.
Yeah Luka, I thought about that - immediately after I hit the "Post" button of course. Hope I'm not hijacking the thread but my question seemed to fit (to me anyway!)
Dan
The metal - pure water is a lousy conductor, of course , chances are the water in the pipe is not terribly pure, therefore, a marginal conductor.
Here in Delaware SOP for years was to ground the main panel ground to a water pipe -- either galvanized or copper, depending upon the builder. The theory being that the metal piping of the house supplied a continous electrical path to earth. This worked pretty well until the water company changed their meters and somewhere inside the meter you lost continuity. Then folks still grounded the main panel to a water pipe and put a jumper wire across the meter. Then NEC started requiring a separate ground rod driven into the earth for main panel ground. Now the local authority requires a driven ground rod and, IF the house has METAL piping, a second connection to the house water piping, said connection to piping must be installed within 6" of the foundation wall ( which always puts the clamp outside of the shut-off valve and meter thus continuing the need for a jumper past the meter in order to ground the entire soldered piping system).
Current NEC requirements.If a ground rod is used as the electrode either it needs to be tested as being less than 25 ohms resistance to ground or a secondardy electrode is needed.A metalic water pipe that is in contact with the ground can be used as a grounding electrode. However, I assume because of the possibility of it being replaced with a plastic or as you mentioned the meter being replaced a secondary electrode is also required.There are several other types of electrodes and they don't require secondard electrodes. A Ufer (metal encased in concrete is one - the metal can be footing rebar).However, if the water piping metalic it still needs to be bonded to the grounding electrode system just as if it where an electrode. Even where it is not needed as an electrode or where it does not qualify for use as an electrode. For example plastic underground supply lines, but copper pipes in the house.
JTC1, Bill, thanks for the feedback.
Because I'm finishing my basement I've been into and around this panel a bunch (I actually needed to add a sub panel) and don't recall seeing any evidence of a second ground. But, then again, I wasn't actually looking for it either. The water meter is inside the house and has a wire feed coming off of it to power a small counter/transmitter outside the house for the meter readers. There is a ground jumper over the meter. The plastic main enters the house near the bottom of the foundation and then connects to the copper via what I assume to be a barbed fitting and a couple of SS worm screw type clamps (a sweet set up I'm sure. It hasen't leaked, yet, but I never look directly at the clamps, fearing they will feel challenged).
So. What I take away from the info you've all provided is if this is my only ground then the system isn't really grounded and I've got issues.
Tell me something, will the lack of a proper ground manifest itself in any way under normal operating circumstances? I've not encountered any weird electrical issues thus far. The GFI's trip when they should, the breakers trip when they should.
Dan
Look inside the panel at the ground bus bar.Look for a #4 or #2 if AL conductor. That will be for the grounding electrode conductor.If the supply conduit is metal and it is properly bonded at the connections at the meter and at the panel then the conduit can be your ground electrode and you won't need a separate wire.However, under the current rules that type of electrode (call a made electrode) either requires testing to prove that it is less than 25 ohms or a secondary electrode.If I following your descriptions the connection to the water pipe is only to bond it to the house system.Now "grounds and grounding" have several different purposes. One is to make the house "one electrically". That means that the stove, the refigerator, the water faucets, etc all the same reference voltage, ie "ground". That is done with the bonding of the water pipe to the panel ground bus bar and the use of a equipment grounding system (the "ground pin" on the receptacle). If there was no ground electrode system of any type you would never notice it within the house. Everything would function just the same.That part does not require any reference to "earth ground". In fact HV transmission lines are worked on hot using baskets hung from helicopters. The first think that is done is that a "ground" clip is run from the basket to the 100 plus kilovolt line. The basket is now "grounded" to the line. It does not matter that it is 100 kv with respect the the earth. So one purpose of the grounding electrode system is to make sure that the "house" is at the nominal reference to the earth. I say nominal because the earth is not a good conductor and there will be voltage drops if the earth is used for a conductor.If there was no local (there are still the ones at the transformer) the only noticable problems would be if you have a pool and you might a mild shock when steping from the pool (bonded to the the house "ground) and the earth by the pool. But in most cases that is caused by the oposite problem. A bad neutral connection forcing the neutral current to flow through the ground electrode and the thus the earth to return to the transformer.The other purpose of the ground electrodes is to provide a path for lightning strike to disapate back to the earth. For that purpose you can't have too many too often.
Bill,
So the water pipe bonding issue is the reason our locals have required grounding to the metallic house piping -- never quite understood this. I always assumed it was a belt and suspenders thing.
Jim
Even if an insulated meter or plastic pipe separates the plumbing in the house from true earth ground, you definitely want to ground it. If it were allowed to float, and a hot wire anywhere in the house came in contact with a pipe, the entire plumbing system would go hot. If the plumbing in the house is grounded, and a hot wire touches it, you get some sparks and trip the breaker.
-- J.S.