RE: [Repeater-Builder] OT- Dispatcher injured by lightning strike
Whenever I read a report like this, I have mixed emotions. I am surprised that the injury occurred, which is impossible if the facility was properly designed and islanded in accordance with numerous standards, including NFPA 70, NFPA 780, and the Motorola R56 Manual. I am also angry that an official issued the statement that ...the communications system, including its 400-foot radio tower, are grounded in accordance with industry safety standards. That official, and the idiots who designed the communications center, should be fired and/or brought up on criminal charges. The key to a safe installation at a location with an on-site tower is to ensure that all utilities pass through a window where a common ground reference exists. Ideally, the tower should be right next to the facility, so that the same ground reference is used for both. The power transformer that feeds the control room should be in that room, not hundreds of feet away, and the secondary neutral of that transformer should be bonded to the same ground that is used by the telephones, radio system, cable TV, satellite system, and raised-floor supports. If executed properly, the design of the control room creates a Faraday Cage within which all occupants are safe from injury due to GPR (Ground Potential Rise) from a nearby lightning strike. Likewise, all the electronics within the control room are protected against surge damage. It is obvious from the news report that the dispatcher was injured because her headset was at a different potential from her body. The GPR resulting from lightning striking the tower led to thousands of volts difference between the radio control system (the headset) and the floor and counter in the control room- and the chair she was sitting in. It is also obvious that this difference in potential could not exist if the tower and the adjacent control room were grounded in accordance with industry safety standards. Some common sense and credible engineering skills are essential elements in a proper control room design. Many moons ago (late 60's), I was Chief Engineer at radio station WLRW, a 50 kW FM station at Champaign-Urbana, Illinois. During my watch, the station control room was relocated to a building next door. It was my job to supervise the cabling installation within the building and to the transmitter at the base of the tower, which was just over 100 feet away. All of the remote circuits and network feeds came through a grounding window that was common with the power and the tower grounding system. I remember arguing with the Illinois Power foreman about how we needed a separate transformer to power the station, and it had to be installed right at the side of the control room and not in a vault several hundred feet away. The value of designing the entire installation to comply with established industry standards and sound engineering practices was proven many times, when the tower was struck by lightning during a storm, and no damage or injury occurred. Although the station was on automation most of the day, we had live talent from late afternoon to early morning, and at least one lightning strike occurred while on-air talent was at the board and wearing headphones. The lights blinked, but the board operator felt nothing and the show went on. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of tracomm Sent: Thursday, July 29, 2010 9:48 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] OT- Dispatcher injured by lightning strike A dispatcher was treated for electrical shock on May 2 after lightning sent a power surge through the dispatcher's headset. http://richmondregister.com/localnews/x1255109983/Lightning-surge-injures-91 1-dispatcher http://richmondregister.com/localnews/x1255109983/Lightning-surge-injures-9 11-dispatcher
Re: [Repeater-Builder] OT- Dispatcher injured by lightning strike
Care to hazard a guess on the percentage of facilities (radio/tv, two-way) that aren't done right? A few years ago this happened near here - a radio personality wearing headphones taken to the hospital following a lightning strike to the tower outside the radio station. Chuck WB2EDV - Original Message - From: Eric Lemmon wb6...@verizon.net To: Repeater-Builder@yahoogroups.com Sent: Sunday, August 01, 2010 11:42 AM Subject: RE: [Repeater-Builder] OT- Dispatcher injured by lightning strike Whenever I read a report like this, I have mixed emotions. I am surprised that the injury occurred, which is impossible if the facility was properly designed and islanded in accordance with numerous standards, including NFPA 70, NFPA 780, and the Motorola R56 Manual. I am also angry that an official issued the statement that ...the communications system, including its 400-foot radio tower, are grounded in accordance with industry safety standards. That official, and the idiots who designed the communications center, should be fired and/or brought up on criminal charges. The key to a safe installation at a location with an on-site tower is to ensure that all utilities pass through a window where a common ground reference exists. Ideally, the tower should be right next to the facility, so that the same ground reference is used for both. The power transformer that feeds the control room should be in that room, not hundreds of feet away, and the secondary neutral of that transformer should be bonded to the same ground that is used by the telephones, radio system, cable TV, satellite system, and raised-floor supports. If executed properly, the design of the control room creates a Faraday Cage within which all occupants are safe from injury due to GPR (Ground Potential Rise) from a nearby lightning strike. Likewise, all the electronics within the control room are protected against surge damage. It is obvious from the news report that the dispatcher was injured because her headset was at a different potential from her body. The GPR resulting from lightning striking the tower led to thousands of volts difference between the radio control system (the headset) and the floor and counter in the control room- and the chair she was sitting in. It is also obvious that this difference in potential could not exist if the tower and the adjacent control room were grounded in accordance with industry safety standards. Some common sense and credible engineering skills are essential elements in a proper control room design. Many moons ago (late 60's), I was Chief Engineer at radio station WLRW, a 50 kW FM station at Champaign-Urbana, Illinois. During my watch, the station control room was relocated to a building next door. It was my job to supervise the cabling installation within the building and to the transmitter at the base of the tower, which was just over 100 feet away. All of the remote circuits and network feeds came through a grounding window that was common with the power and the tower grounding system. I remember arguing with the Illinois Power foreman about how we needed a separate transformer to power the station, and it had to be installed right at the side of the control room and not in a vault several hundred feet away. The value of designing the entire installation to comply with established industry standards and sound engineering practices was proven many times, when the tower was struck by lightning during a storm, and no damage or injury occurred. Although the station was on automation most of the day, we had live talent from late afternoon to early morning, and at least one lightning strike occurred while on-air talent was at the board and wearing headphones. The lights blinked, but the board operator felt nothing and the show went on. 73, Eric Lemmon WB6FLY
Re: RE: [Repeater-Builder] OT- Dispatcher injured by lightning strike
Had a similiar problem when I was chief engineer at an AM-FM radio station. The antenna tower was within 250 ft of the building. The prior engineer connected a copper strap from the automation equipment to one of the tower legs. Whenever we had a lightning strike on the tower you can see the lightning dance across the equipment. Due to the lightning many time I had to replace parts in the automation controller. I finally found the copper strap and removed it from the tower. No longer did I get any calls due to lightning causing automation equipment failure. I then got the owner to get an engineering crew to measure the tower to ground and found that the original grounding was falling and needed to be fixed. After that no longer had issues either with the FM transmitter or TV transmitter at that site. Also added lightning protestion on the AC coming into the building. David Aug 1, 2010 03:43:37 PM, Repeater-Builder@yahoogroups.com wrote: Whenever I read a report like this, I have mixed emotions. I am surprised that the injury occurred, which is impossible if the facility was properly designed and islanded in accordance with numerous standards, including NFPA 70, NFPA 780, and the Motorola R56 Manual. I am also angry that an official issued the statement that ...the communications system, including its 400-foot radio tower, are grounded in accordance with industry safety standards. That official, and the idiots who designed the communications center, should be fired and/or brought up on criminal charges. The key to a safe installation at a location with an on-site tower is to ensure that all utilities pass through a window where a common ground reference exists. Ideally, the tower should be right next to the facility, so that the same ground reference is used for both. The power transformer that feeds the control room should be in that room, not hundreds of feet away, and the secondary neutral of that transformer should be bonded to the same ground that is used by the telephones, radio system, cable TV, satellite system, and raised-floor supports. If executed properly, the design of the control room creates a Faraday Cage within which all occupants are safe from injury due to GPR (Ground Potential Rise) from a nearby lightning strike. Likewise, all the electronics within the control room are protected against surge damage. It is obvious from the news report that the dispatcher was injured because her headset was at a different potential from her body. The GPR resulting from lightning striking the tower led to thousands of volts difference between the radio control system (the headset) and the floor and counter in the control room- and the chair she was sitting in. It is also obvious that this difference in potential could not exist if the tower and the adjacent control room were grounded in accordance with industry safety standards. Some common sense and credible engineering skills are essential elements in a proper control room design. Many moons ago (late 60's), I was Chief Engineer at radio station WLRW, a 50 kW FM station at Champaign-Urbana, Illinois. During my watch, the station control room was relocated to a building next door. It was my job to supervise the cabling installation within the building and to the transmitter at the base of the tower, which was just over 100 feet away. All of the remote circuits and network feeds came through a grounding window that was common with the power and the tower grounding system. I remember arguing with the Illinois Power foreman about how we needed a separate transformer to power the station, and it had to be installed right at the side of the control room and not in a vault several hundred feet away. The value of designing the entire installation to comply with established industry standards and sound engineering practices was proven many times, when the tower was struck by lightning during a storm, and no damage or injury occurred. Although the station was on automation most of the day, we had live talent from late afternoon to early morning, and at least one lightning strike occurred while on-air talent was at the board and wearing headphones. The lights blinked, but the board operator felt nothing and the show went on. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of tracomm Sent: Thursday, July 29, 2010 9:48 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] OT- Dispatcher injured by lightning strike A dispatcher was treated for electrical shock on May 2 after lightning sent a power surge through the dispatcher's headset. http://richmondregister.com/localnews/x1255109983/Lightning-surge-injures-91 1-dispatcher http://richmondregister.com/localnews/x1255109983/Lightning-surge-injures-9 11-dispatcher
Re: [Repeater-Builder] OT- Dispatcher injured by lightning strike
What concerns me more than anythingso many experts yet this sort of thing still happens...(in many fields)!!! Hindsight is great!! D On 01/08/2010 17:24:18, Chuck Kelsey (wb2...@roadrunner.com) wrote: Care to hazard a guess on the percentage of facilities (radio/tv, two-way) that aren't done right? A few years ago this happened near here - a radio personality wearing headphones taken to the hospital following a lightning strike to the tower outside the radio station. Chuck WB2EDV - Original Message - From: Eric Lemmon wb6...@verizon.net To: Repeater-Builder@yahoogroups.com Sent: Sunday, August 01, 2010 11:42 AM Subject: RE: [Repeater-Builder] OT- Dispatcher injured by lightning strike Whenever I read a report like this, I have mixed emotions. I am surprised that the injury occurred, which is impossible if the facility was properly designed and islanded in accordance with numerous standards, including NFPA 70, NFPA 780, and the Motorola R56 Manual. I am also angry that an official issued the statement that ...the communications system, including its 400-foot radio tower, are grounded in accordance with industry safety standards. That official, and the idiots who designed the communications center, should be fired and/or brought up on criminal charges. The key to a safe installation
Re: [Repeater-Builder] OT- Dispatcher injured by lightning strike
And I only see it getting worse as everyone 'has' to cut corners/costs. Chuck WB2EDV - Original Message - From: Doug Hutchison specialq@ntlworld.com To: repeater-builder@yahoogroups.com Sent: Sunday, August 01, 2010 12:53 PM Subject: Re: [Repeater-Builder] OT- Dispatcher injured by lightning strike What concerns me more than anythingso many experts yet this sort of thing still happens...(in many fields)!!! Hindsight is great!! D On 01/08/2010 17:24:18, Chuck Kelsey (wb2...@roadrunner.com) wrote: Care to hazard a guess on the percentage of facilities (radio/tv, two-way) that aren't done right? A few years ago this happened near here - a radio personality wearing headphones taken to the hospital following a lightning strike to the tower outside the radio station. Chuck WB2EDV - Original Message - From: Eric Lemmon wb6...@verizon.net To: Repeater-Builder@yahoogroups.com Sent: Sunday, August 01, 2010 11:42 AM Subject: RE: [Repeater-Builder] OT- Dispatcher injured by lightning strike Whenever I read a report like this, I have mixed emotions. I am surprised that the injury occurred, which is impossible if the facility was properly designed and islanded in accordance with numerous standards, including NFPA 70, NFPA 780, and the Motorola R56 Manual. I am also angry that an official issued the statement that ...the communications system, including its 400-foot radio tower, are grounded in accordance with industry safety standards. That official, and the idiots who designed the communications center, should be fired and/or brought up on criminal charges. The key to a safe installation Yahoo! Groups Links No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.851 / Virus Database: 271.1.1/3043 - Release Date: 08/01/10 02:34:00
Re: [Repeater-Builder] OT- Dispatcher injured by lightning strike
Yup.we are only a number after all!! D On 01/08/2010 18:04:12, Chuck Kelsey (wb2...@roadrunner.com) wrote: And I only see it getting worse as everyone 'has' to cut corners/costs. Chuck WB2EDV - Original Message - From: Doug Hutchison specialq@ntlworld.com To: repeater-builder@yahoogroups.com Sent: Sunday, August 01, 2010 12:53 PM Subject: Re: [Repeater-Builder] OT- Dispatcher injured by lightning strike What concerns me more than anythingso many experts yet this sort of thing still happens...(in many fields)!!! Hindsight is great!! D On 01/08/2010 17:24:18, Chuck Kelsey (wb2...@roadrunner.com) wrote: Care to hazard a guess on the percentage of facilities (radio/tv, two-way) that aren't done right? A few years ago this happened near here - a radio personality wearing headphones taken to the hospital following a lightning strike to the tower outside the radio station. Chuck WB2EDV - Original Message - From: Eric Lemmon wb6...@verizon.net To: Repeater-Builder@yahoogroups.com
Re: [Repeater-Builder] OT- Dispatcher injured by lightning strike
When the expert label starts to get thrown around too much I like to quote one of my math teachers in junior high school whose definition of expert is worth remembering to deflate any over sized egos. Ex is a has been and a Spurt is a drop under pressure Milt N3LTQ Quoting Doug Hutchison specialq@ntlworld.com: What concerns me more than anythingso many experts yet this sort of thing still happens...(in many fields)!!! Hindsight is great!! D On 01/08/2010 17:24:18, Chuck Kelsey (wb2...@roadrunner.com) wrote: Care to hazard a guess on the percentage of facilities (radio/tv, two-way) that aren't done right? A few years ago this happened near here - a radio personality wearing headphones taken to the hospital following a lightning strike to the tower outside the radio station. Chuck WB2EDV - Original Message - From: Eric Lemmon wb6...@verizon.net To: Repeater-Builder@yahoogroups.com Sent: Sunday, August 01, 2010 11:42 AM Subject: RE: [Repeater-Builder] OT- Dispatcher injured by lightning strike Whenever I read a report like this, I have mixed emotions. I am surprised that the injury occurred, which is impossible if the facility was properly designed and islanded in accordance with numerous standards, including NFPA 70, NFPA 780, and the Motorola R56 Manual. I am also angry that an official issued the statement that ...the communications system, including its 400-foot radio tower, are grounded in accordance with industry safety standards. That official, and the idiots who designed the communications center, should be fired and/or brought up on criminal charges. The key to a safe installation Yahoo! Groups Links
RE: [Repeater-Builder] OT- Dispatcher injured by lightning strike
Yup...thats just what I mean...experts.bah humbug!! D On 01/08/2010 19:44:48, Eric Lemmon (wb6...@verizon.net) wrote: That is so true! When you add corporate ego to the mix, things get really murky. A case in point: Back in the mid-eighties, one very large and well-known computer equipment manufacturer was contracted to install some facility monitoring equipment at Space Launch Complex Six at Vandenberg AFB, a site that was to be (until the Challenger disaster) the west-coast Space Shuttle launch pad. The monitoring equipment was divided into two major pieces, on separate floors of the Launch Control Center and about 200 feet apart. From the moment the system was energized, a number of data channels had 60 Hz common-mode noise corrupting the data on the RS-422 circuits. My crew was attempting to investigate the noise issue, when we discovered that the supplier's technicians had deliberately floated the upstairs cabinets by using insulating washers and plastic sheets to avoid contacting any grounded facility items such as embedded rebar. When advised by our AHJ (Authority Having Jurisdiction) inspector that the installation violated Article 250 of the NEC, the manufacturer's engineer explained that this was the way his company did these installations, and- here's the corporate ego part- they had been doing%2
Re: [Repeater-Builder] OT- Dispatcher injured by lightning strike
Often times it's a well-meaning individual that simply doesn't understand (like me - LOL) and there are plenty of inspectors out there that don't know either. The corporate reasons for doing things wrong speak for themselves. Life is full of mis-information. Chuck WB2EDV - Original Message - From: Doug Hutchison specialq@ntlworld.com To: repeater-builder@yahoogroups.com Sent: Sunday, August 01, 2010 3:26 PM Subject: RE: [Repeater-Builder] OT- Dispatcher injured by lightning strike Yup...thats just what I mean...experts.bah humbug!! D
Re: [Repeater-Builder] OT- Dispatcher injured by lightning strike
n5sx...@charter.net wrote: I must admit that I don't see the problem with the sensitive equipment not finding ground thru the floor! In the 1980 I have some telephone central offices built by TRW. Each of the equipment racks were mounted on thick plastic sheets, and the mounting bolts were inserted thru insulating shoulder washers. Each equipment rack had a dedicate home run ground back to the main central office ground buss plate. All worked well, with no lightning problems. Some many years later I was still working for the same telephone company when I was asked to go back to that office to see why the new equipment addition would not work. It was needed badly as the C.O. was out of lines and needed this expansion to work. A quick inspection showed that the new equipment had been mounted directly to the concrete floor with out the insulation kit. I had the CO crew there help jack the rack up and slide a rubber floor mat under it for temporary insulation. We verified that the ground strap was correctly installed, and when we returned that equipment cabinet to service , it came up and worked fine. The equipment installer was forced to return at night to correct his problems. So not everything should be chassis grounded to the floor. Jeff
