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Thread: Question on grounding methods in the roadway

  1. #16
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    Default Re: Question on grounding methods in the roadway

    I will say I can not answer this question!!! that is a tough one!!!!
    Quote Originally Posted by Willis2 View Post
    I would be hooking onto a water utility with a vault containing the pipeline- usually filled with water-that I put one lead into and need to find a ground (Preferably one that does not cross over multiple utilities as would be the case if running a ground wire to the parkway).
    wise men talk because they have something to say and fools because they have to say something....plato

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    Default Re: Question on grounding methods in the roadway

    Quote Originally Posted by 4Q2 View Post
    [CENTER]

    The second trick that you should never admit to using is for working in roadways. Some people claim it's not a valid hookup and won't work but fact is it has worked for me. Just pull your truck up to the manhole or vault, turn on your beacon, turn off your truck, hook your ground to the vehicle frame and go. The mass of the truck should provide enough ground. This also helps out with traffic control. Great for short mark outs, just watch you don't drain your battery.
    Quote Originally Posted by Willis2 View Post
    I would be hooking onto a water utility with a vault containing the pipeline- usually filled with water-that I put one lead into and need to find a ground (Preferably one that does not cross over multiple utilities as would be the case if running a ground wire to the parkway).
    i can kind of get the truck trick, a form of induction i suppose. ~~ if your utility is in plastic? the plastic should shield the water from earth contact correct?
    You Can't Fix It Till You Find It - Jim 3:23

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    Senior Member FiosKing's Avatar
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    Default Re: Question on grounding methods in the roadway

    but how does it work? its not making a complete circuit.....
    "What Are You Doin!?!? GET THE HELL OFF MY LAWN!"
    you have entered a restricted area

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    Default Re: Question on grounding methods in the roadway

    Quote Originally Posted by FiosKing View Post
    but how does it work? its not making a complete circuit.....
    All of us with experience know that you don't need a complete circuit to locate. Think about tracer wires running handhole to handhole. They are unbonded at each end yet you can hook up and trace it out perfectly even though you can see that it is not grounded at the other end. Same thing if you are locating a brand new utility in a new subdivision, it is in the ground but not hooked up yet and we can locate it.

    I always say the higher frequencies give you a false continuity.

  5. #20
    Mke
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    Default Re: Question on grounding methods in the roadway

    I always heard that it all depends what type of equipment you are using.....more like the frequency you are using. I know with my 810 when in a situation where sticking a rod into the ground isn't an option (Inside buildings, marine terminals, aprons, and the like) I connect to when ever is handy. Usually is my Manhole Hook right on top of the pavement. It has even been connected to Manholes that have been removed. The only thing that I have noticed is that you have to get a couple feet further away before locating, but once your locating it, you can bring it back towards the MH, or Panel, or what ever you have been hooked up in.

    The machines that use a lower frequency tends to need a better ground. Although, I don't know if there is any co-relation between the lower frequency or the type of transmitter being used.

    I do know that the 810 can do it.

    Mke

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    Default Re: Question on grounding methods in the roadway

    The higher the fequency the easier a circut is created. The circut is created by higher fequencys bleeding through the insulation of the conductor and going to ground. This is both the blessing and curse of high fequency locating. As anyone who has ever used a pipehorn will tell you.

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    Default Re: Question on grounding methods in the roadway

    Thank you all for the tips and advice.

  8. #23
    4Q2
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    Default Re: Question on grounding methods in the roadway

    Quote Originally Posted by FiosKing View Post
    but how does it work? its not making a complete circuit.....
    Most modern locating equipment works on RF (Radio Frequency) Signals being induced on the utility to be located. RF is AC current and does not require a complete circuit as DC does, only ferrous (metal) mass to travel down and is available as potential energy at the end of this mass. Without getting into the whole Nikoli Tesla/George Westinghouse (AC) and Thomas Edison (DC) battle, try this experiment and you never forget the difference.

    With your 12 volt DC battery disconnected, touch the positive terminal and metal on your truck. Nothing, because the circuit is not complete. But if you touch the negative terminal on the battery, you will feel a slight tingle, circuit complete.

    Now take an extension cord. Stick a nail in the hot leg of the female end. Plug it in and head toward your truck. Grab the nail. Don't worry, it won't hurt you because your non-ferrous. Even though your conductive the potential energy will not enter your body. Now touch something metal on your truck and see if it conducts even though its an open circuit. The "potential energy" has been converted to "work". Enjoy your new hairdo. In electrical engineering lingo the truck is know as a "resistance ground" which differs from an "earth ground" but has the same effectiveness much like the neutral leg in your 110 volt home electric system. That's why the "Truck Trick" works.

    I did want to clarify a few things about these tips I posted though. I only use the "Truck Trick" if I previously located the utility and I always turn the truck off. I don't know if it matters but I know a running vehicle produces RF frequency, therefore bleed-off might effect accuracy of the locate.

    The drill trick is fast, quick and easy, especially good for winter locating but make sure there are no other utilities where you drill your ground rod. Do a passive CATV/Power/Radio if necessary. I don't want anyone to get electricuted. Oh crap, I think I just gave instructions on electricuting above.

    And FiosKing, I do apologize for the posts a couple of weeks ago. I was frustrated because my company had me running all over the state and working a lot of hours. But that's no excuse. My therapist explained the road to recovery is never easy and every once in the while a relapse will happen. But really, Sorry Dude!


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    Senior Member FiosKing's Avatar
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    Default Re: Question on grounding methods in the roadway

    no worries, its all good we all have bad weeks once in a while... pretty interesting truck trick to
    "What Are You Doin!?!? GET THE HELL OFF MY LAWN!"
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  10. #25
    Junior Member Linden Riddle's Avatar
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    Default Re: Question on grounding methods in the roadway

    In the old days, when all split box-style locators were high frequency, there was only one lead--a red wire. You didn't need to ground because the frequency would return "through induction" to a metal plate in the bottom of the inside of the transmitter. Try locating on a higher frequency without a ground--you'll be surprised.

    It's important to remember that this is alternating current leaving the transmitter: half the time the current is going right into earth at the grounding stake. Even with low frequencies, bleed-off occurs because of the grounding stake's position to other utilities. Using higher frquencies and not grounding can actually reduce bleed-off.

  11. #26
    Senior Member Dave72's Avatar
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    Default Re: Question on grounding methods in the roadway

    Quote Originally Posted by 4Q2 View Post
    Most modern locating equipment works on RF (Radio Frequency) Signals being induced on the utility to be located. RF is AC current and does not require a complete circuit as DC does, only ferrous (metal) mass to travel down and is available as potential energy at the end of this mass. Without getting into the whole Nikoli Tesla/George Westinghouse (AC) and Thomas Edison (DC) battle, try this experiment and you never forget the difference.

    With your 12 volt DC battery disconnected, touch the positive terminal and metal on your truck. Nothing, because the circuit is not complete. But if you touch the negative terminal on the battery, you will feel a slight tingle, circuit complete.

    Now take an extension cord. Stick a nail in the hot leg of the female end. Plug it in and head toward your truck. Grab the nail. Don't worry, it won't hurt you because your non-ferrous. Even though your conductive the potential energy will not enter your body. Now touch something metal on your truck and see if it conducts even though its an open circuit. The "potential energy" has been converted to "work". Enjoy your new hairdo. In electrical engineering lingo the truck is know as a "resistance ground" which differs from an "earth ground" but has the same effectiveness much like the neutral leg in your 110 volt home electric system. That's why the "Truck Trick" works.
    :
    People, please do NOT do this !

    An electrical circuit is completed when its a circuit. Depending on the resistance and the capacitance of a path you will get current flow.. it only takes between 1/10 and 1/5 of an amp to kill you.

    Voltage is what works against resistance, frequency works against capacitance. When we bump up the frequency and getting a signal w/o a physical 'path' to complete the circuit, we're actually creating current flow by bridging thru that capacitance.
    (May you live in interesting times)

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    Default Re: Question on grounding methods in the roadway

    In the vault there should be an opening around the pipe (in some cases) and this is where you can ground. Like others have stated use the water in the vault to accomplish the ground. The drill bit trick works along with pouring water (or any liquid that you have) on the ground to make it possible. Connecting to the lid on a manhole or vault can provide an good ground as well. I think we all have used a strange or unusual way to find a ground, just continue to think outside of the box. The truck idea is definitely outside the box, but I have heard of it before and that it works. I never have tried but may soon just to see the results. By the way great question for a beginner in the business!

  13. #28
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    Default Re: Question on grounding methods in the roadway

    Great Thread! and good ideas all around. For my part, I carry an old drop cord that I stripped the ends off of and attached clips to. It's close to 100' long and I keep a couple shorter pieces too.

    The points about higher frequency / no ground methods are very true. I built a short lead for my pipehorn a few years ago and use it to inject more signal on the target while keeping the transmitter further away from a congested area. You just have to be aware of the greater potential for bleedoffs in cases like that and double or even triple place your box before you claim it.
    "You have enemies? Good! That means you've stood up for something sometime in your life." ~ Winston Churchill

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