Re: Elecraft Digest, Vol 196, Issue 17 - Lightning

[Lyn WØLEN]

FWIW, I have never had lightning come in on power, phone, cable or anything
else like that.  All our services are underground for miles prior to
reaching our house, and that probably helps.

We DID have a direct lightning strike on the house several years ago.  It
struck an attic fan on the roof and followed the electrical wiring to the
boxes in the basement, branching out wherever it could and knocking out the
whole electrical system.  In the process, as it blew up boxes and panels, it
blew out a chunk of PVC carrying water from the well into the pressure tank.
And it blew the tank.

It also started a small fire in the attic (insulation), but that didn't do
too much since the large hole in the roof allowed rain to come in for about
5 hours before we returned home from work. The rain, however, caused
sheet-rocked ceilings (especially over the two-story foyer) to sag.  And of
course with no power, the sump pump was out and the basement flooded (to a
depth of about 6 inches until I could run a line from the neighbor's house).

The EMP (or something ...) was apparently strong enough to even knock out
wall clocks that were battery operated.  At our Fire Dept. station (about 2
miles away), the Chief said it sounded like a bomb went off.  We were 30
miles away at the time, but our two little kitties were in the basement and
when I let them out 5 hours later, their fur was still standing on end.

So this is a problem when living in the country where houses are far apart,
there are no power lines to "catch" the lightning and the only physical
connection into the ground of any significance is a PVC pipe going to the
well (which was also blown out thru the wiring).  The lightning actually
exited the house on the natural gas line. The damage was extensive, and we
had to evacuate for 5 weeks.  It was another 4 months or so before
everything was completed (we did some upgrades in the process). Since then,
I have had a lightning protection system professionally installed under the
direction of an engineer who guesstimated our strike at 50,000 amps.

I had no antennas of any sort at the time, but I do now and have protected
it as best I know (see box on QRZ page).

73
Lyn, W0LEN


-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Wilson Lamb
Sent: Sunday, August 16, 2020 8:40 PM
To: [hidden email]
Subject: Re: [Elecraft] Elecraft Digest, Vol 196, Issue 17

I have 2X K3, but am not even qualified to to talk about them.
I CAN say, without reservation, that our antennae are NOT our primary danger
points, at least for those of us with modest (50' and under) installations.
In 65 years of operating all sorts of stuff, I have NEVER seen lightning
damage due to antenna pickup.
I have seen LOTS of damage level stuff come in on phone lines, however!
Most thunderstorms in our area create firecracker discharges in my phone
demarc box, which is just across the basement from my operating area.
They scare me, especially when they occur when I'm disconnecting my
phones/modem, which are connected to the outside world with alligator clips.
I have lost multiple phones and modems to this stuff, when it exceeds the
impressive levels the demarc can handle, but never anything to do with
radio.
This is a great fringe benefit of WIFI.  The stuff we used to lose through
ethernet connections is now airgapped from the modem.
Pulling the plug is almost foolproof protection.
I don't connect computers to radios, so there's an airgap already in place.
When I see the storm coming, I disconnect all radios from their antennae AND
power supplies.
Now, I KNOW lots of people have suffered from antenna pickup, but I'm
betting power/phone lines have produced far more incidents.
Trouble is, if you get a real hit on an antenna, all bets are off and my
experience doesn't matter at all!
If you set up to run from a battery, you can achieve considerable isolation,
especially if you unplug the charger before storms come.
It would be interesting to hear stories of damaging events caused by phone
line transients coming into houses.
WL

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[Bill Frantz]

Our family house a mile up the hill, and my radio shack, has
lightning rods. I've been in buildings with lightning rods two
or three times when they were struck by lightning. Nothing
inside was harmed, but the noise was incredible.

What I don't know is the relation between radio and other
electronic equipment and a lightning rod installation. For
example, do you bond the radio grounds to the lightning rod
grounds? At ground level, or anywhere along the wire?

Too bad I can't find my copy of N0AX's book on the subject. Need
to do more digging.

73 Bill AE6JV

On 8/17/20 at 7:59 AM, [hidden email] (Lyn Norstad) wrote:

>FWIW, I have never had lightning come in on power, phone, cable or anything
>else like that.  All our services are underground for miles prior to
>reaching our house, and that probably helps.
>
>We DID have a direct lightning strike on the house several years ago.  It
>struck an attic fan on the roof and followed the electrical wiring to the
>boxes in the basement, branching out wherever it could and knocking out the
>whole electrical system.  In the process, as it blew up boxes and panels, it
>blew out a chunk of PVC carrying water from the well into the pressure tank.
>And it blew the tank.
>
>It also started a small fire in the attic (insulation), but that didn't do
>too much since the large hole in the roof allowed rain to come in for about
>5 hours before we returned home from work. The rain, however, caused
>sheet-rocked ceilings (especially over the two-story foyer) to sag.  And of
>course with no power, the sump pump was out and the basement flooded (to a
>depth of about 6 inches until I could run a line from the neighbor's house).
>
>The EMP (or something ...) was apparently strong enough to even knock out
>wall clocks that were battery operated.  At our Fire Dept. station (about 2
>miles away), the Chief said it sounded like a bomb went off.  We were 30
>miles away at the time, but our two little kitties were in the basement and
>when I let them out 5 hours later, their fur was still standing on end.
>
>So this is a problem when living in the country where houses are far apart,
>there are no power lines to "catch" the lightning and the only physical
>connection into the ground of any significance is a PVC pipe going to the
>well (which was also blown out thru the wiring).  The lightning actually
>exited the house on the natural gas line. The damage was extensive, and we
>had to evacuate for 5 weeks.  It was another 4 months or so before
>everything was completed (we did some upgrades in the process). Since then,
>I have had a lightning protection system professionally installed under the
>direction of an engineer who guesstimated our strike at 50,000 amps.
>
>I had no antennas of any sort at the time, but I do now and have protected
>it as best I know (see box on QRZ page).

----------------------------------------------------
Bill Frantz        | Art is how we decorate space,
408-348-7900       | music is how we decorate time.
www.pwpconsult.com |          -Jean-Michel Basquiat

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[Jim Brown-10]

On 8/17/2020 3:17 PM, Bill Frantz wrote:
> hat I don't know is the relation between radio and other electronic
> equipment and a lightning rod installation. For example, do you bond the
> radio grounds to the lightning rod grounds? At ground level, or anywhere
> along the wire?
>
> Too bad I can't find my copy of N0AX's book on the subject. Need to do
> more digging.

Hi Bill,

Here are slides for a talk I've done at Pacificon, Visalia, NCCC, and
other local clubs. I worked extensively with Ward on the book. While I
was still working, I gave tutorial workshops on the topic to companies
installing large sound and video systems.

http://k9yc.com/GroundingAndAudio.pdf

The short answer is that EVERY earth connection MUST, both BY LAW
(electrical safety codes) and by good engineering practice, be bonded
together. More of everything is better. :) That means rods, building
steel, metallic cold water plumbing, entry for power, telco, CATV,
antennas. It's also critical that all equipment that is interconnected
be bonded together. That means short, fat copper.

73, Jim K9YC
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