Lightning rod?

[fishheadbob]

I used to live near a television broadcast tower. During a big storm we would crack a cold one then sit in the window watching the tower get hit repeatedly, looked like a scene from Frankenstein, never saw anything wrong with that channel's reception so I figure someone knew what they were doing when that tower went up in the 1950s. We took a look at the tower a few times over the years, the thought struck me that the whole steel tower and all of the supporting guy wires were essentially one big lightning rod that did the job properly.
I have rods on my house and barn that were installed before I was born, judging from the noise and hair raising static I'd guess mine have been popped a few times with no ill effects.
Some people seem to draw lightning more than others. I believe the golfer Lee Trevino has been struck a few times, but I would check that statement out. My wife has been around 3 near misses, most involving water lines. She heads for the basement during a big storm; my great aunt was the same way.

 

[Groo]

Think I'll give it a pass. If something happens now, It'll be on the insurance. If I mess with things and something happens, they might try to blame my meddling.

 

[Fuddy1952]

I was an electronic technician 43 years, retired over 4 years ago. All I know is growing up the two houses on hill top got hit all the time even blowing chimney off. Then lightning rods on everything 60 years ago and not 1 single hit.
In college one instructor said you can't arrest lightning, millions of volts and maybe 50,000 amps for a few milliseconds. Direct strike would vaporize almost anything.
We're close to Thomas Jefferson's Poplar Forest home where they put lightning rods in the big oak trees.
My house is old but in the 60s they put aluminum siding on it, there when I bought it in 1980. It was grounded, I never had a problem... I had it removed, vinyl siding put on late 80s then had problems.

 

[PILOON]

I did a few microwave tower installations for Hydro Quebec years back.
The ground plane called out used many coils of # 6 bare wire in about a 30-50 ft radius all soldered together at the center.
OK that was for electronic 'ground plane' but also served at lightening grounds.

Wet conducts and in absence lots of copper in contact with the earth is needed.

 

[Larry Caldwell]

They simply provide a controlled path (in theory) to ground when a strike occurs, provided they are installed and connected correctly.

That's one way they work. A lightning rod should be sharpened to a point. This results in a very high field gradient around the point, causing corona discharge. In theory, the corona discharge will bleed off the strike before it happens. If a strike still happens, the charge will bleed to ground on the ground wire. A lightning rod does not have to be attached to the house to provide protection. A nice flag pole in the yard is a great place to put one.

 

[Larry Caldwell]

Well, I don't mind saying I'm confused.

So rods dissipate the charge, yet high sky scapers and towers get hit all the time.

A hit can melt a 6 AWG cable, yet grounding systems take hits all the time without damage.

And what of steel roof buildings that are not grounded intentionally and probably only have electrical grounds nearby that never seem to get destroyed if the roof were to get hit and the charge jumps to the nearest electrical line.

I was looking at a pole barn when it took a lightning strike. It was a shower of little lightning bolts all around the building, but the building itself took no damage.

 

[Larry Caldwell]

Yes, grounded systems do drain and prevent static charge buildup, and all things connected are equalized (to ground); but I don't understand how that would prevent a lightning strike. It's the cloud that gets charged up to a huge differential (as compared to the earth), and once the rain drops and anything else conductive provides short enough gaps that the arc(s) can jump to ground: boom!

It's all because old Ben Franklin guessed wrong about the direction of current flow when he discovered lightning was electricity. Lightning bolts do not come down, they go up. The ground is the negative charge with the excess of electrons. Lightning rods only dissipate the excess electrons if they are sharpened to a point.

St. Elmo's fire - Wikipedia

 

[Industrial Toys]

I was once shown lightning rods from OPP towers. They were melted and it was a common thing to replace them.

Most of my amateur UHF/VHF antennas are all DC ground. Very robust and to someone who did not know RF, you would be hard pressed to understand how it would work. It looks like you just bolt this heavy tubular structure to the tower without insulators. Anyway, those antennas are great for lightning.

Then I have this hammy Hamster broadband DISCONE antenna. Once in the approach of a storm I noticed sparks flying across the PL259 Connector. Now, I always try and disconnect the radio attached to it if expecting a storm.

 

[RalphVa]

I live in a relatively flat wooded area. I moved here late last summer. So far this year I've had 2 lighting strikes on trees in my yard. Would a lightning rod save the house? Or just make sure it is the house that gets hit? I was considering getting a standing seam metal roof for the place. Would that change the equation?

I was typing a reply to this a couple hours ago when our power went out AGAIN. Apparently, lightning hit something in the area and knocked out our power and internet (and often our phone).

First thing we did when we bought this house was to have lightning protection installed. Then expanded it to the carriage house when we had it built.

The 2nd house on our road had its chimney all over the road when we came in here looking. Saw another chimney in another neighborhood that was crooked because it had been hit. Figured we needed lightning protection in Virginia.

No hits in 18 years. Of course, we just had a record Ivy Creek flood that made a mess of our property down on the creek, worse than Isabel in 2003. Hope the lightning stays away.

Ralph

 

[Fuddy1952]

I was typing a reply to this a couple hours ago when our power went out AGAIN. Apparently, lightning hit something in the area and knocked out our power and internet (and often our phone).

First thing we did when we bought this house was to have lightning protection installed. Then expanded it to the carriage house when we had it built.

The 2nd house on our road had its chimney all over the road when we came in here looking. Saw another chimney in another neighborhood that was crooked because it had been hit. Figured we needed lightning protection in Virginia.

No hits in 18 years. Of course, we just had a record Ivy Creek flood that made a mess of our property down on the creek, worse than Isabel in 2003. Hope the lightning stays away.

Ralph

Howdy Ralph! You're a Hall living in Virginia and so am I. Could we be kin?