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View Poll Results: AC Voltage Detectors...

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  • Have them, work well.

    7 58.33%
  • Have them, don't waste your money.

    0 0%
  • Don't have them, wish we did.

    3 25.00%
  • Don't have 'em, don't intend to either.

    2 16.67%
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  1. #1
    dazed and confused Resq14's Avatar
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    Lightbulb AC Voltage Detectors

    The Delsar AC Hotstick (also goes by the name of "TAC Stick" I think)
    http://www.delsar.com
    Price: In the $400's

    How many of you use these in your departments?

    We don't, but I wish we did. We have many calls involving power lines, and this would go far in helping everyone stay safe.

    I think some are concerned that hotheads might take lines-down calls into their own hands and will use it to declare downed-wires as "safe." While I'm not sure if I agree with this for your typical lines-down call, there are several situation where I feel it could save lives.

    I'd say its most important use would be to verify power has been shut-down by the electric company. Picture a car-pole MVC, lines down, with subject unconscious in the vehicle. You call the powerco, they dump the grid/area. Wouldn't it be nice to verify a lack of current--especially if you are out in the boondocks with no other signs of electrical use around? Wouldn't you want to know if the lines suddenly become re-energized, either from improperly installed generators or otherwise?

    In general, the Delsar Hot stick can be used to find unexpected voltage, confirm proper power disconnect, and to monitor power shut down.

    Important points:
    - Current must be UNSHIELDED (or have faulty shielding)
    - PROXIMITY sensor - does not require contact with sources
    120 VAC Single Conductor
    15' HIGH SENSITIVITY
    3' LOW SENSITIVITY
    .25' FOCUSED SENSITIVITY

    120 VAC Conductor laying on wet soil
    3' HIGH SENSITIVITY
    1' MEDIUM SENSITIVITY
    .1' LOW SENSITIVITY

    7.2kV Distribution Line (single insulator)
    210' HIGH SENSITIVITY
    70' MEDIUM SENSITIVITY
    20' FOCUSED SENSITIVITY

    46kV and Higher Transmission Line (several insulators)
    >500'HIGH SENSITIVITY
    >200'MEDIUM SENSITIVITY
    >70' FOCUSED SENSITIVITY


  2. #2
    dazed and confused Resq14's Avatar
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    Talking

    From the Hotstick FAQ page...

    ============================== =============================

    How sturdy is the unit? Is it fireman proof?
    No. Nothing is fireman proof but it is "firemen resistant."

    ============================== =============================

    nothing is "fireman proof"... so true


  3. #3
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    Resq14,

    I havenít used the ďHotstickĒ but I would be Very careful about itís use.

    I believe I know a bit about electricity and I wouldnít trust that the power is off just cause the stick said so. And Iím not criticizing the product in any way, in the right hands it probably works great but Iím not sure FF hands are those hands. Once electricity reaches lethal levels (120 volts would do it) there is just no margin for error. 7.5Kv and 46Kv? Man, donít even get me started! Voltage at that level does really wild stuff and I would bet that even the experienced people are uneasy working on or around those lines when theyíre hot (or trying to determine if theyíre hot).

    I guess what it comes down to is this, any ďHotstickĒ is better than no ďHotstickĒ but train, train and train again. Then go get some more training (from your local utility of course). And then, only use it when thereís no other choice because youíll only get one mistake (at 46Kv you may get only half a mistake)

    Just so you know where Iím coming from, I am a volunteer FF and my other profession is as an Electrical Engineer (EE). EEs do all sorts of work with electricity, I happen to be a wuss and so wonít work with anything over 15 volts which is commonly referred to as ďdigital electronicsĒ. The electrical industry has plenty of stories about people who have been killed when there hands moved faster then their brains (to be fair some fatalities are truly accidents but most accidents can be avoided), even experienced engineers and techs make mistakes. When I first got into the business (25 years ago) I plugged myself into 220 volts and made my heart go pitter-patter (its really not suppose to do that) so I got the message early and leave the lethal voltage to people smarter (or dumber, depending on you perspective) than me.

    By the way, our departments policy is that we can look and advise (wires down kind of call) but we leave all things electrical to the utility (our local is very good about responding ASAP for structure fires).

  4. #4
    dazed and confused Resq14's Avatar
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    Do you simply look and advise on car-pole MVC's with lines down and entrapment? Do you wait for the powerco to arrive? How would you handle that? Say the car caught on fire, and the person could not get out. What would you do?

    Odds are, you're going to do something. After phoning the powerco and having them dump power, someone would try to do something to help.

    We do attend training provided by the local electrical company, Central Maine Power. They have a public safety division that provides excellent courses for the public, as well as first responders.

    I'm not one for messing with electricity either. So when they say "we've shut the power off" (which they WILL do provided it is a life-threatening situation) I'd like something that I could hold in my hands to confirm this. It's not always possible to wait 30-40mins for the powerco to arrive. Furthermore, the situation can be monitored just in case things should change midway through the operation.

    How about confined space entry? Wouldn't you want to know if something was energized before you start climbing down to rescue the unconscious worker who could've been electrocuted? Without them, we'd just be climbing down and wondering whether it was safe. Sure, you can ask bystanders and co-workers if it is safe, but wouldn't you like to test it yourself? Kinda like atmospheric monitoring...

    I just see this as a safety device that all departments should have, assuming they work as advertised. I'm curious from departments that do have these: do they work well?

    An important point: 120V will kill you just like 7200V will. The body isn't a perfect conductor of electricity, but passing through the chest it takes only 0.05 amps to kill. 0.05 amps. So theoretically, your average 15 amp circuit has enough juice behind it to fry you 300 times over. Something to think about.
    Last edited by Resq14; 10-04-2002 at 12:22 PM.

  5. #5
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    Resq14,

    Yes, if a MVA has knocked a utility pole down and primaries or house service lines are on the ground near or directly on the vehicle then very likely we will wait for the utility to come and shut it down (or make sure its dead). Of course we use some common sense and if its obvious that there is little or no threat then we go to work.

    Same rules apply to confined space.

    Perhaps the difference for us is that we have an agreement with our local utility, if we tell them that its life or death, they come right now (often in just a few minutes).

    I have been zapped more times than I care to remember, anybody that deals with electricity can tell the same story (talk to a commercial electrician for really scary stories) and Iím suppose to know better. Which of course, is the point I was trying to make. Even when you know (some of) what you are doing, you still donít and canít know everything.

    I agree, it would be the most useful to hear from departments that have used the ďHotstickĒ.

    One last point. You canít talk about voltage or current as single entities, they are related to each other in ways that get really complicated and would make a very long, boring post (and it would not have been complete or accurate, high voltage is not my specialty) so I didnít try.
    But here is a quick example of what I mean:
    Lightning has been measured at a million(s) of volts and thousands of amps but it doesnít kill everyone it strikes. Why not? I donít know exactly except that the combination of volts, amps, watts and duration werenít right.
    I would and have grabbed the terminals of a 5 volt 20 amp power supply, you canít feel it and it has no effect on you. Why? Because the voltage/amp combination isnít right to kill me.
    I can feel voltage at about 50 so I choose not to work on anything higher than that.

  6. #6
    dazed and confused Resq14's Avatar
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    Originally posted by WHF
    Of course we use some common sense and if its obvious that there is little or no threat then we go to work.

    I would and have grabbed the terminals of a 5 volt 20 amp power supply, you canít feel it and it has no effect on you. Why? Because the voltage/amp combination isnít right to kill me.
    I can feel voltage at about 50 so I choose not to work on anything higher than that.
    WHF...

    First, this (to me) is what gets people killed. What is obvious and common sense to some people--with respect to electricity--isn't to others. IMHO, the line is always unsafe, unless.
    1. A linesman standing beside me says it is safe (always preferred)
    or
    2. They remotely cut power and I have a way of reliably monitoring this in a LIFE THREATENING situation...making the operation as safe as we can until the powerco arrives.

    Second, some terms are being interchanged here. Wattage is a function of BOTH voltage (like PSI) and amperage (like gpm). The current must be strong enough to overcome the inherent resistance (like friction loss) in your skin and body, and still have enough amperage to have a harmful effect on the heart. The 0.05amp figure is the minimum threshold to induce V-Fib internally across the heart. Obviously if the current is being conducted into an extremity...through the body... and out, it will take more than 0.05amps.

    This really isn't all that complicated. For a great and succint discussion, read here. It explains why AC is usually more dangerous, why amperage is important, and why the path of electricity flow through your body is important.
    http://www.merck.com/pubs/mmanual_home/sec24/278.htm

    And your 50v/20amp "hands-on" thing... sounds like it was a battery or another DC power supply. If it was AC, then you had some high resistance and/or were insulated somehow.
    Last edited by Resq14; 10-06-2002 at 12:28 PM.

  7. #7
    Forum Member Rescue101's Avatar
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    14,I've got some experience with both the "hotstick"and the voltage detector made by TIF instruments.I'll offer my views some of which coincide with yours.While useful, I wouldn't want to put my life in the hands of either of these fine tools.The only time I'm confortable with anything over 120vac is if I have a lineman standing beside me or I have seen him physically ground it or remove it.Outside of that you are ALWAYS AT RISK.Some D**b A** down the road with an illegally installed generator cranks it up and you're toast.In the case of your 55 I'd probably use a LOT of forethought and some powder.Our Dept. SOG's state no ops until grid is double confirmed down.I want the lines grounded if they're down.I think either instrument will serve you well if you use them as intended and with a bunch of training in it's use around anything electrical in your neighborhood.Oh did I mention that electricity makes me nervous?T.C.

  8. #8
    Forum Member Fire304's Avatar
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    Originally posted by WHF
    Perhaps the difference for us is that we have an agreement with our local utility, if we tell them that its life or death, they come right now (often in just a few minutes).
    Must be nice, around here "right away" means they'll show up in 30-60 minutes. I had to baby sit a 7200V primary for 4 hours in the pouring rain, right across a busy town road, every time dispatch called the powerco they were "on the way" and "should be there shortly" finally after 4 hours they said it would be at least 2 more before they could come. Meanwhile I have a 1" primary power wire across the road with all sorts of idiots trying to drive around me so they could get to the other side of town ("No you CANNOT go over that wire"), and I had no idea if it was hot or not.

    An example of a situation where a hotstick would have been good to have happened recently. We got a call for wires down at a construction site. Found 2 dumptrucks with drivers inside with multiple wires across both trucks. One truck had dumped his load, pulled forward and with bed up pulled down one pole and damaged two others.

    Ariving on scene I could tell the guy who did it was nervous, overwieght, smoked like a chimney and was sweating bullets. What if his ticker decided it was time to take a break? Do we just stand there and watch him die? We called for the grid to shut down, and it did, nearby stop light shut off, but how do we know if those wires actually on the truck are turned off? Luckily we did not have to test our luck, powerco showed up in 30 minutes and confirmed our lines safe.

    Are there any "safe" ways to ground a power wire? If you could, the ciruit breaker would pop. Also would short out any generators that might back feed a grid.

  9. #9
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    Speaking as both an electrician and a FF to my knowledge there is no "safe" way to ground out a power line. I have on scenes cut the wires on a secondary line, and wire nut them off, but this was an emergency situation involving an entrapment from an MVA. Basically I work with electricity day in and day out, and still would just sit there and wait (5-6 hours) for the power company before any action.

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