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Thread: 60 cycle/Power modes

  1. #31
    Senior Member headcipher's Avatar
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    Default Re: 60 cycle/Power modes

    There's always the last resort of calling a trouble shooter or cable tech to get right on the wire and open up anything that you're not allowed to.

    They're usually willing once they realize that if they come out to help now it can prevent coming out later and doing a bunch of repair.

  2. #32
    Member PokerAdam's Avatar
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    Default Re: 60 cycle/Power modes

    Remember, locating with 50/60, radio, or any other mode (witching) where you do not have to hook-up to the pipe or cable you are trying to locate is a passive mode.
    This means you are detecting something from the signals that are inherent to the facility.
    Sure 60hz is on most cable that is connected to a termination point (pedestal, transformer).
    If the line is active, it can usually be found passively. Rarely can you detect a street light during the day, because there is no power running through it.
    But did you know that there is a static charge associated with gas flowing through plastic. The signals aren't very strong, but sometimes, with the right passive machine, you can find a plastic gas main, although I do not recommend this.
    Sometimes water mains will be detectable passively, but the conditions of the environment have to be perfect. Especially if the main is creosote.
    Phone, CATV, Power are all manufactured to be good conductors so can usually be found passively, although a utility that is well grounded will show up as a quiet spot on the CAT.
    I do not use a passive mode to mark out any utility that I have not verified by hooking up. But it is a great resource when you have checked your prints, verified your utility and have a long way to go between hook up points. Sometimes passive mode will allow you to continue when your active signal has long faded away.
    My favorite passive locator is an RD CAT. I have found when performing multiple way locates, you can discern by the sound, what utility you are on.
    Yes this is only a tool an experienced locator should use. Even then, with caution.
    My favorite experience using a CAT was on a private locate in an industrial area. I had just finished finding all the stuff I could with my 810. To double check everything, I broke out my CAT and ran a grid through the area. I found several old pipes and various cabling running all over the place. I was able to find the termination point (inside the buildings) by dropping on the passive signal and running them out with my 810. I love putting together the puzzle.
    Last edited by PokerAdam; July 25th, 2012 at 11:19 PM.

  3. #33
    Senior Member headcipher's Avatar
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    Default Re: 60 cycle/Power modes

    I've never heard of a creosote main. Do you mean a concrete or asbestos/concrete main? I have only heard of creosote being used as a coating for power poles and railroad ties.

  4. #34
    Senior Member UULC's Avatar
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    Default Re: 60 cycle/Power modes

    Back around 1890 to 1910 water mains were made of wood. They were tongue & groove with a thin metal strap wrapped around it. They used creosote to coat it. I use to have a piece of one but when it dried out it fell apart. to tap it they drilled a hole in it. back in the 90's when we had a lot of rain it would push and we thought we had a main leak. We would take a old shovel and whittle it down and plug a hole.

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    Default Re: 60 cycle/Power modes

    I have been told that thee re tat type of water mains still in use in selected parts of chicago

  6. #36
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    Default Re: 60 cycle/Power modes

    Yup the good ol' 810 - CAT combo. Works everytime. The best of both manufacturers - in the same industry.

  7. #37
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    Default Re: 60 cycle/Power modes

    Quote Originally Posted by headcipher View Post
    I've never heard of a creosote main. Do you mean a concrete or asbestos/concrete main? I have only heard of creosote being used as a coating for power poles and railroad ties.
    Yes, Concrete - These water mains (aquifers) were put in a long long time ago.

  8. #38
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    Default Re: 60 cycle/Power modes

    Quote Originally Posted by UULC View Post
    Back around 1890 to 1910 water mains were made of wood. They were tongue & groove with a thin metal strap wrapped around it. They used creosote to coat it. I use to have a piece of one but when it dried out it fell apart. to tap it they drilled a hole in it. back in the 90's when we had a lot of rain it would push and we thought we had a main leak. We would take a old shovel and whittle it down and plug a hole.
    Thanks UULC, I am a locator, this was what the Water Dept. guys told me it was made of.

  9. #39
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    Default Re: 60 cycle/Power modes

    Quote Originally Posted by paintitnow View Post
    I have been told that thee re tat type of water mains still in use in selected parts of chicago
    And parts of New York and New Jersey.

  10. #40
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    Default Re: 60 cycle/Power modes

    Quote Originally Posted by DigScout View Post
    Yup the good ol' 810 - CAT combo. Works everytime. The best of both manufacturers - in the same industry.
    If I were to start my own company (pipe dream) this is what I would issue to the field. (Plus alot of other stuff you have to beg management to get you.)

  11. #41
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    Default Re: 60 cycle/Power modes

    I agree with GPGrasshopper. Power mode is not a locating mode but a verification tool once dots are on the ground and if necessary to see if you are on the right utility your trying to locate. Over head power lines can and will affect the power mode signal and when trying to locate multiple duct pkgs it is recommended that you start with a riser and then induct separately. When I first started I was not even allowed to have 50/60 or radio options in my equipment for 1 full dig season. A wise decision

  12. #42
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    Default Re: 60 cycle/Power modes

    Quote Originally Posted by Locates with a cape! View Post
    Power mode is over-rated. Its funny....all the guys I know that don't have the capability insist on telling me for 5-10min how much easier they're life would be if they had the ability to use "power mode." They could just hop out of they're truck and start locating power, cable tv etc.....and its true, an experienced locator with power mode can easily determine the different tone that is made while using power mode over cable TV and power (power is much more grungy) but its just asking for problems...anyone who tells me how much they want/need it puts off a red flag of lack of quality to me right off the bat.

    I use power mode/radio mode for some passive sweeps after I am done with all my locates, and just sweep a grid like motion over the excavation area. Not once has it ever found something I wasn't able to find with careful 810 sweeps. However it can be useful to determine electrical trenches as starting points to locate signals to they're sources, if you are in a situation where you don't have access to buildings and some vaults may not be accessible due to locks or being paved over it can be a useful tool. Or if your following a utility u know is by itself through area's of "fill" you can sometimes utilize these modes to have a good idea of where the target facility might be going while its really deep. Things here and there more or less...

    On several occasions, I have performed a full utility locate for design/survey or what have you, and now that I am done marking im curious on what will be picked up passively, and to what accuracy...so i bust out the RD-4000..... Some times power mode puts me directly on top of my marks, but Ive noticed a large percentage of the time it is actually off by about 6 inches to a foot....not sure why - maybe it has to do with multiple cables being in the ditch or different harmonics on the cable itself coming back down the line? I can only speculate...but I am an accuracy kidna guy...6 inches to a foot can make or break a dig for you contract locators... but anyways yes power mode does have some usefulness, but the way i look at it as follows: I am going to be marking power through dig scopes by either clamping the primary in a vault or another 'better' non passive hookup anyways, I am never going to 'solely' trust power mode with peoples lives and my reputation at stake, so when all is said and done, i might sweep with it passively when im done....but when you are dealing with multiple utilities i wonder what the point even is sometimes. One or two other situation its been extremely useful is on rural mountain roads with telco on one side of the road power on the other...stuff like that but not practical save me time on jobs left and right kinda tool. Just another way to "verify" what you should have already found out by other means.

    Anyone have any hard facts about why power mode tends to be ever so slightly "off" ? I am interested to find out if anyone has some insights that im not privy to on this just for curiosity sake.
    I agree with this... It's not something to use to save time-that will usually result in a damage. The RD40000 is probably the strongest but the RD8000 has a different tone in power mode depending on the cycle to differentiate between facilities like cable and electric but you really have to know what you're listening for and what's in the area. The only time I ever use power mode is for final sweeps or under extenuating circumstances. Ocassionally you'll have an electric network with locked manholes and no access to transformers within reason. This is usually in really dense urban areas and you're basically straight-lining from mh to mh and marking duct packages but I still wouldn't just jumpout and power mode the locate without knowing what you're doing and without locating everything else first. It can also help with verifying some tricky concentric lines as well but still more of a verification tool since it's definitely less accurate to pinpoint.

  13. #43
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    Default Re: 60 cycle/Power modes

    I think it was in 2007 that CLS took some receivers from certain locators and replaced them with ones that did not have radio and power mode. Seems they were using it as their primary locating mode. The passive modes (radio & power) I use as a trouble shooting or verifying application.

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