ARLA/CLUSTER: Radioamador Electrocutado quando instalava a sua antena.

Segunda-Feira, 14 de Julho de 2008 - 12:43:11 WEST

 Estatisticamente, esta é provavelmente a actividade, instalação de antenas, a mais arriscadas para um radioamador, e aquela onde se registam mais acidentes muitos deles infelizmente fatais ou muito incapacitantes.

È bom que quando nos dedicamos a esta actividade não descuidemos a nossa segurança.

João Costa
CT1FBF

-----Original Message-----
From: twiar-bounces  mailman.qth.net [mailto:twiar-bounces  mailman.qth.net] On Behalf Of Greg Williams
Sent: segunda-feira, 14 de Julho de 2008 4:16
To: twiar  mailman.qth.net
Subject: [TWIAR] Ham electrocuted in Kansas City

This is from the ARRL PR reflector. I hope this adds to the words of caution that Mike and I provided on tower climbing. It is so sad that this type of accident still occurs.

Plan for safety and look at the work area for dangers. These can be burried power lines, overhead power lines, out of date or inspection safety equipment and any trip hazzards. Tripping on a toolbox or having an eight foot ladder fall on you can make for a very bad day.

Think safe and be safe my friends!

Paul Guido, N5IUT

From: Larry Staples lstaples  k.....
Date: July 13, 2008 8:19:25 PM CDT
To: Larry's List
Subject: A ham and his son electrocuted?

KC0TIG and his son were electrocuted today while trying to put up an antenna.

<http://tinyurl.com/6btuas <http://tinyurl.com/6btuas>>

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

<http://tinyurl.com/66988d <http://tinyurl.com/66988d>>

<><><><><><><><><><><><><><>

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 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

--

Gregory S. Williams
gregwilliams(at)knology.net
k4hsm(at)knology.net

http://www.etskywarn.net
http://www.twiar.org
http://www.icebearnation.com

_______________________________________________
TWIAR mailing list
TWIAR  mailman.qth.net
http://mailman.qth.net/mailman/listinfo/twiar