lightning rods any believers ?

[JB4310]

Question for JB...Looking at your pictures, the second picture shows a church roof that is shingled. Looking closer at the shingles...I see a lot of raised areas on the shingles. What are they? Roofing nails that have popped up? Or something else?

That is a 110 year old slate roof, a very high quality slate (monson black) and what you see are copper snow guards. There are a few different types on this roof. Some are wire loops that were put on when the roof went on, some were retro fitted over the years, they just slide up between and under the slate and catch the top edge of the slate with a fold in the sheet metal.

This is a high and steep roof, the gutter is over 50 feet off the ground and the peak is 90 feet high. I've seen pictures of the old timers installing those little snow guards from bottom up, they would get a row started and just lay a 2x4 on that row and keep moving up. no fall protection, just a 2x4 out in the middle of the roof 3/4 the way up. That takes some nerve.

On the bottom a couple feet up from the gutter there is a steel pipe snow guard system that is supposed to hold the snow back, but it still builds up to the point of forcing past and damaging the snow rails crashing down to the ground. I never get to hear it cause I'm home tucked into my bed, but the priests or others that live in or near slate roofed buildings always use the same term to describe what it sounds like "A freight train"

We had a hard winter and the snow rails took a beating.

This building is very well covered with lightning protection, almost every picture I have you can see the braided wire or spikes. you can see some in the last picture. The only problem is it is very old and I know there are breaks in the bonding. I will start looking closer at it in the future, maybe propose some serious repairs.

JB

 

[Redbug]

Thank you JB. That is very interesting. I did not think of slate, nor snow guards. Living down south it did not enter my mind about ways to hold snow. I see the lightning spikes and it looks like there are a few pigeon spike strips there, too. That looks like interesting work. I can't believe the steepness of those roofs. The idea of safety has come a long way.

The building where I work also has a system of lightning rods on the roof. It is a flat roof, and the rods are spaced about every 50 feet or so all over the roof. All rods are attached to a thick wire cable that goes to a main ground. The main ground looks a little bit like a well head down inside a manhole with a manhole cover.

On towers, I have installed what we call, "porcupines". These look like a flower with each petal being a metal spike that points outward. Each spike sheds electrons to the atmosphere and decreases the odds of a strike. The electric companies use these a lot, also. Sometimes, you will see the spikey things installed at the power sub stations.

 

[CBW1999]

About 8 or 9 years ago I had a wood handled shovel get hit by lightning while I was digging with it. It pretty well blew the spade part completly off. Me, I think I just lost a little hearing and, of all things, most of my eyebrows (but they grew back...with a vengence! )

I don't suppose that you bought that shovel at Harbor Freight.......sorry couldn't resist!

I have a 110 year old farm house in Northern Vermont. When we bought it, there was the remnants of a lighting rod system on it. All that was left was 1 "spike" that had 2 glass balls intact and some of the heavy gauge cable running along the roof. Interestingly, I have been told that the decorative glass balls were meant to shatter if there was a strike and that was you visual cue to inspect the system and house for damage.

Having lived here for 10 years, we have experienced many severe electrical storms. Several bright flashes with concurrent thunder but never any evidence of the house being hit. One tree about 15 feet from the house appears to have some scarring but, nothing definitive.

Overall, I basically believe that if there is enough energy present to send millions of volts, miles through the air- there isn't a whole lot we can do to control or divert it.

Now...only to muddle the whole idea about being the highest point around and being a "target"- what about earth sheltered homes? Our well driller said he has had to repair/replace pumps due to lighting discharge through the ground (physical damage to the pump, not the wiring). So, would haveing an earth sheltered home increase the risk to its occupants?

 

[Redneck in training]

Here is my theory. Assuming the current flows horizontally trough the ground and the ground having resistance there will be a voltage drop. In example if the current is 1000 000 A and the resistance is 1 ohm there will be 1000000 V across the resistance. Needless to say that the intensity of the current most likely decreases proportionally to cube of distance from the strike. If the strike is close enough there can be significant voltage generated across the house or in example across the cable to the pump.

 

[George2615]

Sorry I can't answer the OP's post but I did ask a minister one Sunday if he had faith. He said he surely did. Then I said well, if you do have faith why are there lightning rods on the roof of the church. The minister couldn't answer but said I have a good point.
I guess they are there for those that don't have faith.

 

[jonyyuma]

RedBug, the spiny bushes of wire might be lightning array, a totally different type of protection_ TO Prevent a lightning strike....Usually connected to a chemical ground rod.

 

[retiredmgn]

We could debate this all day -the truth is there is no truth. Lightening is beyond our control. The original barn here was struck in 1954 and obliterated. Worthy of note: there wasn't a tree within miles over 10 feet tall. That said, 10 years ago our well head - towering 12 inches off the ground was hit and was fried.
I have been keeping a 32' sailboat off the coast of Maine for 10 years. People in the same anchorages who have all sorts of lightening poles, big squiggle metal balls to dissipate the charge to prevent their boat from being fried, large metal plates hung in the water to ground the boat...get blasted at the same rate as someone like me who does nothing.
It's out of our hands.
Garrison Keillor
"Be well. Do good work and write home often"

Follow Garrison's words. If you're taken unexpectedly, at least you know ya done the best you could.

 

[retiredmgn]

don't be sitting on the toilet in a lightning storm

no shat. Do you know this from experience?

 

[Redneck in training]

I used to work for a telecom many years ago. We were not allowed to enter the switch if storm was in the area for good reason. We had our office on one side and the toilet was on the other side of the building with the switch in between. One time I had to go during a storm and while walking along the switch I saw lightning jumping from one equipment row to another. The rows were about 4ft apart. No problems at the toilet though.