Announcement Announcement Module
Collapse
No announcement yet.
Light Up A SeeSnake? Page Title Module
Move Remove Collapse
X
Conversation Detail Module
Collapse
  • Filter
  • Time
  • Show
Clear All
new posts

  • #16
    Re: Light Up A SeeSnake?

    Originally posted by SewerRatz View Post
    Now I no not rely on inductive or energized locating for sewer work, what I do use it for is when I can not pick up the sonde in my camera right away. I have had sewers that has taken some odd turns and for the life of me I could not pick up the sonde at first. So I would energize the line which would help me go in the right direction, once I got the direction of the line finding the sonde was a snap.
    This is the proper usage for the technique shown in the video. I would never advise anyone to use this technique to mark the location of a sewer line. Locating the sonde will be far more accurate and eliminate the variables associated with line tracing.

    In terms of grounding, the technique demonstrated in the video was done in an ABS line. Without water in the line there was no detectable signal, with water in the line there was plenty of signal. Because of this, and because of the relatively low frequency used (33kHz, though it also worked at 8kHz), I tend to think that it was not coupling capacitively.

    Guy

    Comment


    • #17
      Re: Light Up A SeeSnake?

      Originally posted by SewerRatz View Post
      It is hard to pay attention to turns when you are deep inside a factory or high rise basement. 99% of the time I can figure out where my sonde is. There is just the rare times I have to energize the line, I have noticed that other lines get energized but I never get fooled.

      I have other contractors hire me to locate the sewers for them cause they where off with their own locate. My preferred tool to locate non-metallic sewers is our 30+ year old Goldak. I went on one job I taped on the transmitter sent it down the line and when I went to locate I was in the same spot as the contractor was. So I pulled out and went back to that same spot and still got a signal right at the spot I just was at. So now this is where the old tech shines, I went back to the transmitter and tuned my locater frequency to give off a tone that was very distinct compared to the one out front which was the false tone. Ran the line back in to the trouble spot. Went out front, heard the false tone, then walked around and picked up the tone I was looking for. With these newer locaters that have a set frequency they are looking for and it wont let you easily distinguish a false signal over the one you are looking for.

      Locating utilities, just like cleaning drains takes some skill that is learned over time.

      Yep. I have 4 PB-44's. I use one almost daily. I build my own transmitters from tape-ons for 3" and up all the way down to one that will fit in 1/2" PVC conduit when taped on to an electrician's fishtape. Goldak wants too much for their transmitters. There's only $5 worth of parts involved. And they are too damn big.

      I have found the interference you've noticed most often comes from TV's or just about any kind of computer / logic / commo gear. If you adjust the tone to the "other" side of the null (the spot where you lose it) often the interference will be shifted away so you can hear the transmitter, just as you describe.

      Comment


      • #18
        Re: Light Up A SeeSnake?

        Originally posted by irguy View Post
        This is the proper usage for the technique shown in the video. I would never advise anyone to use this technique to mark the location of a sewer line. Locating the sonde will be far more accurate and eliminate the variables associated with line tracing.

        In terms of grounding, the technique demonstrated in the video was done in an ABS line. Without water in the line there was no detectable signal, with water in the line there was plenty of signal. Because of this, and because of the relatively low frequency used (33kHz, though it also worked at 8kHz), I tend to think that it was not coupling capacitively.

        Guy

        Interesting. Thx for the info.

        I'll bet it's still coupling capacitively tho' - the water (with conductive impurities) coats the inside of the pipe, the pipe itself is non-conductive (insulator), then the fill surrounding the pipe is slightly conductive.

        Conductive layer followed by non-conductive layer followed by conductive layer = capacitor.

        I just went and checked with the DVM to see if the SS camera head / spring is electrically connected to ground back through the wiring - it is. 4.7 ohms for a 200' Mini. This is what makes all this possible.

        Comment


        • #19
          Re: Light Up A SeeSnake?

          Originally posted by Vance G View Post
          Interesting. Thx for the info.

          I'll bet it's still coupling capacitively tho' - the water (with conductive impurities) coats the inside of the pipe, the pipe itself is non-conductive (insulator), then the fill surrounding the pipe is slightly conductive.

          Conductive layer followed by non-conductive layer followed by conductive layer = capacitor.

          I just went and checked with the DVM to see if the SS camera head / spring is electrically connected to ground back through the wiring - it is. 4.7 ohms for a 200' Mini. This is what makes all this possible.
          This would be how Seesnake Heads that come in contact with live voltage get smoked... I knew they had to have a path to ground for this to happen... Sorry thinking out loud

          Comment


          • #20
            Re: Light Up A SeeSnake?

            Keeping the signal on the target line ONLY is hard to do if you're running of a wall receptacle.
            Vance, wouldn't an isolation transformer help this (keep your signal from backfeeding over the AC supply)?
            ---------------
            Light is faster than sound. That's why some people seem really bright until you hear them speak.
            ---------------
            “If I had my life to live over again, I'd be a plumber.” - Albert Einstein
            ---------
            "Its a table saw.... Do you know where your fingers are?"
            ---------
            sigpic http://www.helmetstohardhats.com/

            Comment


            • #21
              Re: Light Up A SeeSnake?

              OK great some good info! So since the inductive clamp on the seesnake cable is not super accurate can I just set my 10 watt on the interconnect cable coiled and have the same or near results? Or would I be even more off the mark?
              Seattle Drain Service

              Comment


              • #22
                Re: Light Up A SeeSnake?

                Originally posted by Bob D. View Post
                Vance, wouldn't an isolation transformer help this (keep your signal from backfeeding over the AC supply)?
                Nope. The trace signal goes back through the ground, which bypasses the xfmr windings.

                Comment


                • #23
                  Re: Light Up A SeeSnake?

                  Originally posted by Cuda View Post
                  OK great some good info! So since the inductive clamp on the seesnake cable is not super accurate can I just set my 10 watt on the interconnect cable coiled and have the same or near results? Or would I be even more off the mark?
                  Cuda:

                  It isn't the method of getting the signal on the cabling (inductive, conductive) that's the problem, it's that you can't KEEP the signal on the target line (pushrod) that's the problem. And that it can be difficult to get the push rod to accept signal using inductive technique vs. conductive in the first place.

                  Example:

                  If you coiled up your interconnect cable on the floor, and set your xmtr on the coils, and there was a 110V circuit just under the slab in the same place or even nearby, you will very likely wind up tracing the electric line, NOT the pushrod. The electric line is a much better target, electrically speaking.

                  Using the "set the transmitter on it" method is fraught with danger, especially inside a structure. You will even energize metal studs. Try it sometime when you're at a site where they are using them. It'll scare the hell outta you how many things you DO NOT want to find will have signal all over 'em.

                  I would imagine that a 10W transmitter will create a "no trace" zone around itself of perhaps up to 50' where you can't trace the line because you are just picking up the transmitter directly. I don't know because I have NEVER run into a situation where I needed that kind of signal strength. If I am having low signal problems, it can be fixed by changing frequencies, getting a better transmitter ground, getting a cleaner electrical connection to the target line, etc. You ALWAYS want to use the minimum amt. of signal necessary to get the job done to minimize cross coupling. Just dumping more signal onto the target can cause more problems than it will solve.
                  Last edited by Vance G; 08-28-2010, 02:52 PM.

                  Comment

                  Working...
                  X