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Lightning rods

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Anarchist420

Diamond Member
Feb 13, 2010
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The house owned by my parents has them, but why do some houses not have them? Isn't it unsafe to have a roof that doesn't have a good grounding path and without any lightning rod(s)? My older brother's house in NC doesn't have any and it was built in 94. My oldest brother's house was built in the 1950s (in Virginia) and it does have one.

I would never live in a house without one, but some people who live in a house without them aren't bothered by not having them.

I remember that right after they built my alma mater's apartments they caught on fire because the complex was struck by lightning and there were no lightning rods. IIRC the complex wasn't even one month old before it caught on fire.

And yes, I know that under some circumstances not even lightning rods will protect buildings from catching on fire once the building is struck by lightning.
 
C

Crono

Lifer
Aug 8, 2001
23,720
1,502
136
Lightning hitting houses is relatively rare, so people risk it.

More likely it will hit a tree, or that a tree will hit your house.
 
edro

edro

Lifer
Apr 5, 2002
24,326
68
91
I live in an old 1800s house and it has 3 lightning rods with thick steel bars connecting it to the ground.

I have no idea why they went away through the years. Probably because they didn't help much.
 
vi edit

vi edit

Elite Member
Super Moderator
Oct 28, 1999
62,484
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edro said:
I have no idea why they went away through the years. Probably because they didn't help much.
Click to expand...

Have to wonder if they are more risk than they are actual prevention. And if they can be installed poorly causing even more risk.
 
Modelworks

Modelworks

Lifer
Feb 22, 2007
16,240
7
76
I believe the change in architecture of buildings is what is responsible for the decline of lightning rods on homes. If you look at older homes they tend to be more narrow and build upwards with lots of peaks in the roof line where newer construction tends to have a more flat roof with less of a pitch. Lightning goes for the highest point that has the most surface area and older homes tend to have those high points.

My grandmothers home had lightning rods and it does get you a discount on insurance so it is something to consider if you are really concerned.
 
lord_emperor

lord_emperor

Golden Member
Nov 4, 2009
1,380
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vi edit said:
Have to wonder if they are more risk than they are actual prevention. And if they can be installed poorly causing even more risk.
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This.

Install rod to protect from lightning => lightning burns house down => lawsuit => nobody wants to install them any more.

Even if they are a net benefit, people don't understand that "reduced chance" does not mean 100% protection.
 
A

Anarchist420

Diamond Member
Feb 13, 2010
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I don't see many new homes built without them at least not in virginia.

I had thought the cylinder style ones reduced the risk as long as they were installed right. Of course, I could be wrong about that.

IIRC, I read that there were one kind designed in britain and one kind designed by Ben Franklin and that those were more dangerous than none at all, but that the newer cylinder ones were good protection.

Anyway, my parents' house was built in 90 and doesn't have a flat roof (it has high and low points), and so I guess that's why it has lightning rods. Still, the CNU apartment complex got struck and caught on fire and it had a completely flat roof if I'm not mistaken.
 
Last edited:
Modelworks

Modelworks

Lifer
Feb 22, 2007
16,240
7
76
Anarchist420 said:
Anyway, my parents' house was built in 90 and doesn't have a flat roof (it has high and low points), and so I guess that's why it has lightning rods. Still, the CNU apartment complex got struck and caught on fire and it had a completely flat roof if I'm not mistaken.
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Another huge factor is the terrain and population of the area. If there are lots of homes and the homes are built close to each other so that if you were to draw a line across the tops of the homes and that line is mostly flat then you are not likely to get a lot of strikes because the tops of the roof lines form a more natural average of ground levels and the home that peaks above that line or trees that peak above that line would become the lightning attraction point.

In the past you had a lot of homes that might be located in the middle of a field or spaced hundreds of feet apart and that would make them more of a target, sort of like standing up in the middle of a field during a storm, you are the high point for lightning to attract to.
 
Modelworks

Modelworks

Lifer
Feb 22, 2007
16,240
7
76
vi edit said:
Have to wonder if they are more risk than they are actual prevention. And if they can be installed poorly causing even more risk.
Click to expand...

The other factor is that when installed properly lightning rods are not attractive home items. I remember my grandmothers setup and it was the most unattractive part of the home. Across the roof there were about 6 spikes located on the peaks, off of each spike ran a 1 inch round galvanized metal twisted metal cable that followed the roof to the edge and then straight down off the roof into the ground. There were 6 of these cables on one side of the home, each was supported by ceramic insulators away from the home.

People don't want to buy homes that have large cables running down the sides.
 
A

Anarchist420

Diamond Member
Feb 13, 2010
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Modelworks said:
Another huge factor is the terrain and population of the area. If there are lots of homes and the homes are built close to each other so that if you were to draw a line across the tops of the homes and that line is mostly flat then you are not likely to get a lot of strikes because the tops of the roof lines form a more natural average of ground levels and the home that peaks above that line or trees that peak above that line would become the lightning attraction point.

In the past you had a lot of homes that might be located in the middle of a field or spaced hundreds of feet apart and that would make them more of a target, sort of like standing up in the middle of a field during a storm, you are the high point for lightning to attract to.
Click to expand...
Well, the homes in my area aren't very close to each other.
 
A

Anarchist420

Diamond Member
Feb 13, 2010
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Never mind. I'm retarded. I realized those cylinders apparently aren't lightning rods after looking them up on wikipedia. Lightning rods are something completely different.
 
lxskllr

lxskllr

No Lifer
Nov 30, 2004
60,107
10,568
126
Anarchist420 said:
Never mind. I'm retarded. I realized those cylinders apparently aren't lightning rods after looking them up on wikipedia. Lightning rods are something completely different.
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Plumbing vents? :^D

Do any of you know why the old lightning rods had glass balls on them? My 2 thoughts are purely decorative, or as an indicator of a strike. I was thinking they would break if they got hit, so you'd know something happened. I'm not sure about the value in that, but...
 
guyver01

guyver01

Lifer
Sep 25, 2000
22,135
5
61
lxskllr said:
Plumbing vents? :^D

Do any of you know why the old lightning rods had glass balls on them? ..
Click to expand...

The idea was that glass objects, being non-conductors, are seldom struck by lightning. Therefore, goes the theory, there must be something about glass that repels lightning. Hence the best method for preventing a lightning strike was to bury a small solid glass ball in the tip of the highest shaft.
 
herm0016

herm0016

Diamond Member
Feb 26, 2005
8,516
1,128
126
lighting rods primary purpose is not as a ground path, but as a way to draw charge off of the roof of a house. secondary is a path to ground in case of a lighting strike. they should be called lighting repellent rods.
 
lxskllr

lxskllr

No Lifer
Nov 30, 2004
60,107
10,568
126
guyver01 said:
The idea was that glass objects, being non-conductors, are seldom struck by lightning. Therefore, goes the theory, there must be something about glass that repels lightning. Hence the best method for preventing a lightning strike was to bury a small solid glass ball in the tip of the highest shaft.
Click to expand...

Ah, thanks. That's always been a bit of a curiosity to me. I've always liked lightening rods, but I've never seen them on a house newer than 80 years old or so. I don't think they really use them on new construction around here.
 
Jeff7

Jeff7

Lifer
Jan 4, 2001
41,596
20
81
It's because no one's reanimating the dead anymore. They're all too busy playing on Xboxes and cellphones and computers.
 
M

masteryoda34

Golden Member
Dec 17, 2007
1,399
3
81
guyver01 said:
The idea was that glass objects, being non-conductors, are seldom struck by lightning. Therefore, goes the theory, there must be something about glass that repels lightning. Hence the best method for preventing a lightning strike was to bury a small solid glass ball in the tip of the highest shaft.
Click to expand...

Yeah but right above that paragraph you copied from Wikipedia without attribution it also says:

The main purpose of these balls, however, is to provide evidence of a lightning strike by shattering or falling off.
Click to expand...

http://en.wikipedia.org/wiki/Lightning_rod#United_States
 
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