Message Board Thread - "Downed power lines"

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Downed power lines blueberry 6/23/2011
Unable to find a firm answer. If a power line is down can the TIC determine if it is energized? I understand the radiant heat will be detected....but in time if the line cools and it is obvious with the use of the TIC, is that enough evidence to determine the line is not energized. Any other info. on downed power lines and the use of the TIC would be welcomed. Thanks
 
Re:Downed power lines jvoitl 6/23/2011
Don't even try it. If there is no current flow there will be no heat and you won't see anything. Stay away and call your local utility provider. Relying on IR to tell if a line is dead could be a fatal mistake.
 
Re:Downed power lines blueberry 6/23/2011
If there is no current... the line is not energized...correct
 
Re:Downed power lines dandersen 6/23/2011
Where are you finding these downed power lines to scan?

"If there is no current... the line is not energized...correct"
Correct?

Not "no", but hell no.

I will quote Dr. Madden (if he doesn't mind); "you got a know as much about what you're looking at as what you're looking at it with".

I highly recommend that you take your camera and yourself and get as far away from anything electrical as possible…

 
Re:Downed power lines blueberry 6/23/2011
Just for the record any downed line is considered "enrgized" that is a given..........but these are questions that arise in TIC classes often. It is a legit quest. If a line does not show heat via the TIC why would nt you think it was not energized? Im just searching for an educated and reasonable resonse from someone that actually has been educated on this matter. Thx to all
 
Re:Downed power lines Bob Berry 6/24/2011
If a line is energised and was under 100% load then I would expect it to show some heating on the conductors. However if there is only 10% load then I would not expeect it to heat sufficiently to allow detection. Without knowing the load you could not make a safe call as to whether it is down or not. And of course if you know the load, then you dont need the camera.
 
Re:Downed power lines jvoitl 6/24/2011
Plug in just an extension cord with nothing plugged into it. There is no current flow to generate heat, but it IS ENERGIZED..
 
Re:Downed power lines Top Gun 6/24/2011
Here are some thoughts. Perhaps danderson refers to Dr. Bob Madding. To the point: danderson is correct in stating that blueberry should get as far away from anything electrical as possible. Anyone who says “If there is no current... the line is not energized...correct” is rationalizing and justifying their actions based on a premise such as just stated. This is what kills folks! When anyone deals with electricity with this attitude, they are placing their life in their hands. Electricity is invisible – period. A thermal camera will not see it as well. There are instruments that will detect electric fields, and the proper use of one of these will determine whether or not the conductor is energized. Ohm’s law governs electrical circuits and has three components: Voltage, Current and Resistance. The IR camera can see the effects of two of these: Resistance and Current; yet it is the flow of electrons or Current over a resistance that causes heat. The National Electrical Code exists to ensure electrical safety and fire prevention. They have established standards for the amount of current that a conductor of a certain size will carry without overheating. Overheating is based on the thermal tolerance of the material used for insulating the conductor from its surroundings. Most wire insulations are made of plastic. Overhead power lines are bare, or not insulated. So if a wire is carrying its 100% rated current, it will heat to near the thermal rating of the insulation, which usually is stamped on the outside of the wire in degrees C., which is usually quite hot. The illustration that jvoitl uses with the extension cord is a great example of why one should always assume a downed wire is energized. VOLTAGE is present without Current. In my view, voltage is electron pressure, the energy that drives electric force. Force does work. Heat results from work. Connect your body to an energized conductor, and your body will become a conductor for the electric current which will work on you. The mere presence of electricity in the body causes muscles to contract, the heart to stop. The flow of electricity can cause external and internal burning. These are all too awful to just blindly “play” with.
 
Re:Downed power lines blueberry 6/24/2011
Thanks for the responses. I will try to put some of that in layman's terms.
 
Re:Downed power lines dandersen 6/25/2011
Better yet, take some real training courses and quit being a layman...

It is very unsettling as I look across the Internet of all the "camera owners" (untrained thermographers) that project their ability to conduct thermal imaging on so many different types of applications without knowing anything about the application to start with.

When inspecting high-voltage gear, you can be killed deader than dead by simply pointing a ballpoint pen (or your camera stylus) at something in the switch yard!
 
Re:Downed power lines HarleyD 6/27/2011
There are many reasons not to touch a downed power line and not one to touch it. I use a tic (tick tracer) on the end of a fiberglass pole to identify if a line is energized or not. Even then I do not touch it until I have verified that the utility has locked out the line. With all the proper PPE on you are still at danger but you have minimized the risk. An example is that if two lines are running in parallel and one is down at one end and denergized the other line that is running in parallel could be creating a current through EMF causing one to receive an electrical shock when touching the downed wire. Don't ever touch a downed power line!
 


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