[RFI] Question re: Whole House Surge Protection
eedwards at tconl.com
Wed Jul 21 22:15:26 EDT 2004
One more thing to be aware of in the fine print of most of those power
company power protection services: They probably won't cover lightning
energy coming from anywhere else except the power feed. So if your antenna
gets hit and smokes everything within the house, they won't cover you for
anything. They typically only pay if their device is taken out by a direct
hit to the power line. Even stuff damaged by EMP by a nearby strike won't
be covered. In my opinion, they're pretty worthless.
Tom is correct in that the way in which you ground and bond things and
route cabling can account for whether or not you'll have problems due to
lightning. I'm amazed by Tom's boldness to go without a single surge
suppressor, but that shows his confidence in his installation practices.
It's not always intuitive how to correctly route cables and how to
correctly bond and ground things especially in a home compared to a comm
bldg. Even professional comm techs are not always aware of the proper way
to do these things. Many times they like to make things "look nice" when
that can do a great deal of damage when lightning strikes.
I recommend looking at Polyphaser's web site which has many tutorial papers
on it. Also, if you can get your hands on a copy of Motorola's R-56 comm
site standard, it has many good recommendations and drawings of various
layouts that can add to your ability to do things the right way. (e.g.,
never bend a ground wire by more than an 8 inch minimum bend radius. Every
bend adds impedance as seen by lightning energy.) Polyphaser also has a
booklet that is pretty thorough that's worth the money.
If you run into anything specific that your not sure about, post a question
here and see what this crew here has to say about it! Good Luck.
73, de ed -K0iL
From: Tom Rauch
Sent: Wednesday, 21 July, 2004 7:33 PM
To: Eric Rosenberg; rfi at contesting.com; towertalk at contesting.com;
pvrc at mailman.qth.net
Subject: Re: [RFI] Question re: Whole House Surge Protection
> My neighborhood was zapped on July 4th. An indirect hit
> powerline surge at our house that nailed my Omni-6+ and
> (wireless phone, answering machine, home alarm control
> Oddly, while our hit came trhough the AC line, my
neighbor was hit
> through his cable connection (our TVs were not hit).
The first thing I'd do is review the proper way to ground
your utilities and radio feedlines. I'd be willing to bet
neither you nor your neighbor have good single point grounds
for all wiring entering the buildings, and do not use single
point hubs at TV sets and the like.
Every feedline entering the dwelling should be through a
grounding block that has a very low impedance to the telco,
CATV, and power line grounds.
When that isn't done, lightning loops through the building
and wipes out all sorts or equipment in weird ways, and a
lightning protector almost certainly won't do a thing.
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