[PPRAANet] Fw: Kansas City Kansas Ham electrocuted today

[Dick-w0raa]

Good grief, be careful out there!!!!

Dick W0RAA

http://www.kmbc.com/news/16871003/detail.html

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



  >>>
  >>>THESE NEWS ITEMS MOTIVATED CHUCK KRALY, K0XM, TO WRITE THIS MESSAGE:
  >>>
  >>><><><><><><><><><><><><><><>
  >>>
  >>>I just saw this one on the news, and had to write a this message to be
  >>>passed on to the ham community, especially the newer hams.
  >>>
  >>><><><><><><><><><><><><><><>
  >>>
  >>>We lost another ham today, and it is a very sad event. The parties
  >>>involved, were installing a Comet FIBERGLASS antenna, that came in
  >>>contact with a single 7620V power line. Now how do I know what the
  >>>exact voltage is? I built and maintained the substation that fed this
  >>>circuit. I spent 27 yrears as a substation technician for the Board of
  >>>Public Utilities. I am still in this field. So, I feel I have some
  >>>experience in what I am passing along.
  >>>
  >>>In a nutshell, the location of the accident was a few blocks from the
  >>>substation. The wires you see going thru the residential areas are AT
  >>>MINUMUM 7200 volts from each wire to ground, and between any two of
  >>>them is 13,800 volts. This is nothing to play with at any time. I have
  >>>seen a fault TOTALLY vaporize 1" copper buss (which is solid). Imagine
  >>>what it can do to a human.
  >>>
  >>>Each wire is fed from what is called a 3 phase line. From there, it 
can
  >>>be broken off and sent down a property line as a single wire.  Those 
are
  >>>called "laterals" Yes, you will see a device at the break out point,
  >>>and this is a fuse. BUT the caution needs to be conveyed.  These fuses
  >>>are in the 60-100 amp range. This is at 7200 volts. On top  of that,
  >>>anytime a tree falls across a line, or a pole gets hit, there  is a
  >>>circuit on the "feeder" at the substation that AUTOMATICALLY closes the
  >>>feeder back in, and TRIES to restore the power to the area.  Some of
  >>>these "reclosers" can operate 2-5 times, depending on how they are set.
  >>>Now from the substation end, the protective device is set for  the full
  >>>fault capabilites of the line. In the case of BPU, this can  be set at
  >>>600 AMPS, and multiples of that value. The protective  devices are set
  >>>for what is called a "time" or and "instantaneous"  operation. Picture 
a
  >>>fast blow fuse and a slow blow, and you will  understand the difference
  >>>in the settings. These setting are at  multiple of the 600 amp value.
  >>>So, if there is a direct short, then it will not trip until it reaches 
a
  >>>value at, oh lets say, 8 times that value. So we are looking at 4800
  >>>amps. and this is at 7200 volts and lower. So, it trips, then it
  >>>energizes it AGAIN. The possiblity of survival is slim and none.
  >>>
  >>>Now remember how I said they were installing a FIBERGLASS antenna? 
Well
  >>>guess what. It is metal inside. Yes, fiberglass does not radiate  as we
  >>>all know. Hence the metal. That is what caused the accident.  They got
  >>>too close to the line (remember your 'magnetic lines of flux'  theory?
  >>>If not, look it up on the web). There is a minimum approach  area that
  >>>MUST be followed. This changes for ALL voltages. This  distance must 
NOT
  >>>be broken. If it is a flashover will happen, and it  is not pretty.
  >>>Electricity will find the shortest path to ground. In  this case it was
  >>>a couple of men.
  >>>
  >>>Folks, this is nothing to take chances with. In my almost 30 yrs as a
  >>>ham, and 27 yrs in the power utility field, I have seen way too many
  >>>"accidents." Stop, look and if it is close or SEEMS that way- DON'T.
  >>>Find another place. High voltage lines are NOT forgiving. Your life
  >>>depends on it. You always hear "it is the amps not the volts" well I
  >>>can tell you when you get at these levels, who is going to argue what
  >>>killed the person who had the accident. PLEASE, PLEASE follow the
  >>>warnings. ANYWHERE close is too close.
  >>>
  >>>Stay safe, and I hope we can enjoy many more years of hamming.
  >>>
  >>>Thanks Guys,
  >>>
  >>>Chuck Kraly, K0XM