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[TowerTalk] 2 Hams electrocuted - more info

Subject: [TowerTalk] 2 Hams electrocuted - more info
Date: Mon, 14 Jul 2008 18:21:00 EDT
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KC0TIG and  his son were electrocuted today while trying to put up an  

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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 substaion 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 substaion that AUTOMATICALLY  
closes the  fedder 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 substaion 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

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