Message: 1 Date: Tue, 15 Jul 2008 10:20:32 -0600 From: "Bruce Rattray" Subject: [qrp-canada] FW: [skcc] Ham and Son Electrocuted To: "QRP-Canada Reflector-" Message-ID: Content-Type: text/plain; charset="iso-8859-1"
*** WARNING!! *** -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Cliff Fox KU4GW Sent: Tuesday, July 15, 2008 7:40 AM To: 3895_Group; NCXMS Group; W4ERT ARES RACES; SKCC Group Subject: [skcc] Ham and Son Electrocuted Ham and Son Electrocuted Filed under: Ham Radio by Bob Olsen at 10:21 am on Monday, July 14, 2008 A ham radio operator and his son were electrocuted Sunday while trying to put up an antenna in Kansas City, Kansas. Details are here. These deaths motivated Chuck Kraly, K?XM, to write this cautionary message. 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 7,620 volt 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 7,200 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 7,200 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 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 7,200 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. James KB7TBT NEGARC Activities Manager www.kb7tbt.com www.ne4ga.org www.myspace.com/kb7tbt J. Bruce Prior 853 Alder Street Blaine, WA 98230-8030 360-332-6046 Amateur Radio Station N7RR Grid CN88px _________________________________________________________________ Keep your kids safer online with Windows Live Family Safety. http://www.windowslive.com/family_safety/overview.html?ocid=TXT_TAGLM_WL_family_safety_072008_______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
