[R-390] Grounds

[odyslim at comcast.net]

I remember living in Savannah GA. I was a military brat and we moved
quite often. Georgia was one of the scariest places I have ever lived.
We constantly had terrible thunder storms and hurricanes.

 I will never forget the day when a lightening ball came in the house.
We ran out. The house didnt burn but I thought it was going to.

Regards, Scott

----- Original Message -----
From: Flowertime01 at wmconnect.com
To: R-390 at mailman.qth.net
Sent: Fri, 31 Jul 2009 00:04:31 +0000 (UTC)
Subject: Re: [R-390] Grounds

Dave,

You were commenting on multiple grounds.

The problem with lighting is it reaches out and touches a lot of points at 
once with lots of power. The electric company thinks every day 24 x 7 at 100 
amps and 240 volts. What is good design for this is not good enough for 
lighting.

Once you put a zillion amps on a point, the voltage drop and current across 
a conductor to the next point become a big voltage drop at lots of current 
with makes for a power spike best measured joules and micro seconds or less. 

This is the part of lighting strikes that cause parts of nice electrical 
devices to become molten metal and eject with great energy from what we 
consider closed containers.

Once you do the real math a few times on practical electrical systems for 
lighting strikes, you want to pull all the wire out of the house and hide in 
the sand every time it gets cloudy.

The conduct from one end of home to the other when energized by lighting 
exhibits a large voltage drop from end to end and large current rush. For that 
split second during the flash, every thing has more potential than even the 
Myth buster can muster and it is trying to reach a state of zero 
differential.

For near misses good grounds do work. You know not how many spikes go by 
unnoticed. Between these two extremes better grounds will save you from bigger 
closer strikes.

I have my antenna wire unhooked from the house and grounded outside in the 
yard where the antenna feed line drops down. I think I have a fair ground 
that is code compliant and currently just under a year old.

I have surge protectors on the computers. 

I turn off the TV and radio in the flash.
I have a battery weather radio, I unplug it when it comes on and tells me 
we have a weather watch.

No dish washing, No washing machines No TV no phone calls. Let the thing 
ring and the answering machine deal with it. No computers. no showers when it 
rains.

When we hit the road I unplug every thing but the refrigerator.

I do not get an insurance discount for this but I have never had to file a 
claim just because it has not struck close to me again.

When I was about 4 years old my mother put me on my bed and told me to stay 
put. My two little sisters were on one of their beds and told to stay put.

My Mom was washing dished in the kitchen sink when the house was struck.
The neighbor come over to tell my Mom the house was on fire and found my 
mother on the kitchen floor. (back in the days when we did not have locked 
doors). My Mom survived and is still doing well today. But I am a believer. I 
was a loud bang.

Roger

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