Date: Sat, 8 Jun 1996 19:13:15 -0700 (PDT) From: Michael Dillon <michael@memra.com> To: inet-access@earth.com Cc: linuxisp@lightning.com, freebsd-isp@freebsd.org Subject: Re: Zzzzzap! (fwd) Message-ID: <Pine.BSI.3.93.960608191225.20036B-100000@sidhe.memra.com>
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I think we may have the definitive answer to lightning protection here... Michael Dillon ISP & Internet Consulting Memra Software Inc. Fax: +1-604-546-3049 http://www.memra.com E-mail: michael@memra.com ---------- Forwarded message ---------- Date: Sat, 8 Jun 1996 20:02:23 -0600 From: Dale Ludington <lazarus@LASCRUCES.COM> Reply-To: Small Internet Access Providers <IAP@VMA.CC.ND.EDU> To: Multiple recipients of list IAP <IAP@VMA.CC.ND.EDU> Subject: Re: Zzzzzap! On Thu, 6 Jun 1996, Terry Kearns wrote: > -- [ From: Terry Kearns * EMC.Ver #2.3 ] -- > > Anyone got any serious advice about lightning protection? The little surge protectors that you buy from Radio Shack and the like are next to useless. Generally speaking they will protect up to about 2.4 Kv. I've measured in residential locations with surges as high a 7 Kv and on locations with large motor controllers up to 10 Kv. Lightning will blow through the small suppressors like tissue paper. The primary cause of lightning damage is the leakage of voltage between disparate voltage potentials. If the voltage in all points in a device is equal then there is no leakage and therefore no damage. A device known commonly as a "lightning arrestor" made by Delta Lightning Arrestors will acomplish this equalizing of voltage potentials. The device is located as close to the power company point of attachment on the building as is practical. The National Electric Code allows the device to be attached in the meter socket _without_ any fusing or disconnecting means and this is the preferred method of connection. How it works is very simple. All leads, power, neutral, & ground, are bonded to a common pellet of a semi-conductor that will conduct freely above 170 volts per phase or leg. When lightning strikes the voltage rises, the semi-conductor conducts and all conductors become the same voltage potential. With all conductors having equal voltage no shorting will occur. No real current is involved so the wire leads are only #12 copper. I personally have over 30 years experience with these devices and I have not known of one to fail. They are slow to respond however and should be used with an industrial Transient Surge Suppressor such as is made by Leviton. These will handle surges as I described above. I use this combination and I have survived several lightning strikes with no damage what so ever. BTW, the Delta's are cheap, about $25 plus installation for the 240 volt one and about $59 for the 480 volt versions. +++ Dale +++ INTERNET de Las Cruces 1004 W. Hadley Ave. Las Cruces, NM 88005 Office (505) 525-8578 Fax (505) 525-8437 ****************************************************************************** I'm sane, but I'm overwhelmed.... I'm tired, but I'm working.... Alanis Morrissette, 1996 ******************************************************************************
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