Rich: I find much of what you state as pabulum for the press. Many of Mr. Clarks 'facts' are assertions. For instance he quotes the requirement for parallel guys to be separated by at least one foot and then he shows a violating example where the guys are almost orthogonal. He shows grass near the guys like these are examples of where the ignition could start. Ask a fire fighter that has ever backfired and they will tell you must light the base, not the top of the grass.
His arc points? Lighting damage, ESD, or corrosion? You also speak of transmission neutrals. Where do you find transmission neutrals? Three phase transmission lines don't have neutrals. Occasionally in lightning country they will place a grounded overspan. To be effective such a span must be grounded at every pole or tower. No overspans are shown in any pictures. Fred Townsend DC to Light Inc. [email protected] wrote: Second, if the lines would go arcing all day, under nominal load, the arcing would NOT have gone unnoticed. Nominally, the guys are tight. When we have severe winds (as in October), one of the two guys may become loose as the wind blows on the pole and it bends. Arcing is not likely to be continuous. The transmission lines cross mountains and deserts, and most of their path is away from populated areas and roads. Often, the transmission line neutral is earthed at each end of the transmission line. This would give rise to current in the earth. It all comes down to the question of probability of dry grass, bad contact and current transients, multiplied by the number of poles in the region. Powerpoles are commonly in dry grass. With winds, contacts can be intermittent. Thousands of powerpoles. Best regards, Rich - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Text inserted by Platinum 2007: This message has NOT been classified as spam. If it is unsolicited mail (spam), click on the following link to reclassify it: http://127.0.0.1:6083/Panda?ID=pav_240108 <http://127.0.0.1:6083/Panda?ID=pav_240108&SPAM=true> &SPAM=true - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
