Why do flamingos stand on one leg?

[JanelleNica]

I have an 80 ft metal tower that is cemented into a dirt ground. It houses two small antennas to send and receive signals for wifi. This tower's power source is not a home. It has a dedicated line that runs directly to its own power meter. This tower is about 300 ft from a concrete home. The Internet company says the tower itself is already grounded. I have other people who are saying it is extremely dangerous to not have it properly grounded with a copper rod. What are the potential dangers if lightning were to strike this tower? I live in Nicaragua where reliable knowledge is hard to find! I would appreciate any insight!

 

[berkeman]

I have an 80 ft metal tower that is cemented into a dirt ground. It houses two small antennas to send and receive signals for wifi. This tower's power source is not a home. It has a dedicated line that runs directly to its own power meter. This tower is about 300 ft from a concrete home. The Internet company says the tower itself is already grounded. I have other people who are saying it is extremely dangerous to not have it properly grounded with a copper rod. What are the potential dangers if lightning were to strike this tower? I live in Nicaragua where reliable knowledge is hard to find! I would appreciate any insight!

Welcome to the PF, Jane.

Can you take a few pictures and use the UPLOAD button to post them here? Do you see any cable to a grounding rod at the base of the tower? Where is the power meter? The grounding mechanism may be part of that section...

 

[Baluncore]

The Internet company says the tower itself is already grounded. I have other people who are saying it is extremely dangerous to not have it properly grounded with a copper rod. What are the potential dangers if lightning were to strike this tower?

The grounding requirements of metal towers are well understood and followed by the engineers who specified and installed the tower. If the metal tower was not properly earthed, a lightning strike could damage the concrete footings or the radio equipment on the tower. Damage to the concrete footings might allow the tower to fall. The internet company and installation engineers do not want that to happen and so will have installed one or more reliable lightning conductors across the concrete from the tower to the ground. You can probably see that bare metal conductor at the base of the tower where it crosses the concrete footings and enters the ground. Go take a look and see what method was used to Earth the tower. The lightning conductor will be separate from the power supply ground.

You and the concrete house have no more to fear from lightning than usual. You are probably slightly safer with an 80 ft tower, 300 ft away, than without the tower. Indeed it would actually be safer if the grounded tower was closer to the concrete house.

There is no possibility of the lightning getting into the local power grid from a grounded tower. Lightning is always striking the power company's grid of wires, which are designed to survive lightning, so things are as safe as they ever were, even with the tower nearby.

The tower will have been properly grounded. You may have found some people who like to get their fun by spreading fear, uncertainty and doubt.

 

[mfb]

@Baluncore: In North America and Europe: Sure.
In Nicaragua: ?

 

[Baluncore]

Nicaragua follows the NEC standards. Are you suggesting that the wiring code in Nicaragua is insufficient? Or that the local power supply authority would allow a meter to be connected without proper grounding of both the power supply and of the structure?
The internet company is not an uneducated electricity thief, they need a reliable system. Not grounding the tower structure would be a false economy.

 

[davenn]

@Baluncore: In North America and Europe: Sure.
In Nicaragua: ?

Nicaragua follows the NEC standards. Are you suggesting that the wiring code in Nicaragua is insufficient? Or that the local power supply authority would allow a meter to be connected without proper grounding of both the power supply and of the structure?

@mfb is hinting at, and I kinda agree, Nicaragua is a 3rd world country and what I have seen in many 3rd world countries, that I have visited, is that rules and reg's are rarely followed and mains / all cabling is usually pretty bad

heck for that matter, I have seen some horrific 120V mains house wiring even in the USA in my visits there that made me cringeDave

 

[Baluncore]

The Internet company says the tower itself is already grounded.

If that is truly the situation, then there is no problem.

BUT IF the tower is not grounded, there are two worst case possibilities;
1. The footings are destroyed by a massive lightning strike and the tower falls. The closest it could get to the house is 220 feet away.
2. The tower could deliver the lightning to the local supply. Before the tower was placed there, the overhead supply cables were probably the direct target for local lightning. The supply will have survived previous strikes, so it must must be safe, correctly earthed and protected.

I see no reason why a poorly earthed 80 ft tower would have safety implications to a concrete building 300 ft away. There is no evidence that the tower is poorly earthed, that was just suggested by some uneducated FUD-mongers.

You can't blame an entire country for your poor expectations. The more you describe Nicaragua as a 3rd world country with poor wiring standards, the more it will fulfil that expectation. Nicaragua is where it is today because of the political and economic actions of 1st world countries.

If the Chinese build the Nicaragua Canal to compete with the Panama Canal, will you belittle Nicaragua even more?

 

[JanelleNica]

Thanks everyone for your quick responses! The tower IS NOT grounded, the wifi company said it is buried in the ground therefore "naturally grounded".

The tower has 4 cables cemented in the ground to also hold it in place. My biggest worry is not the tower falling over.

My worry also has nothing to do with damaging the equipment as it is guaranteed to be replaced by the wifi company.

My biggest fear is that it could be unsafe and somehow zap someone near the house... I was told upon a strike that if all that energy is not grounded then it is very dangerous to anyone nearby.

 

[Baluncore]

My biggest fear is that it could be unsafe and somehow zap someone near the house... I was told upon a strike that if all that energy is not grounded then it is very dangerous to anyone nearby.

If it is not well grounded, then nearby probably means within 12 ft of the base of the tower or of a guy wire.
You will be quite safe at the house.

 

[JanelleNica]

What a relief! Thank you so much for the information.
I have one more question for you: This tower's original power source was a water pump that is connected to the house about 100 feet away. I am switching it over to the independent power source of a meter. While waiting for the power company to make the installation, it is still hooked to this water pump. There is a breaker at the water pump that connects to the tower. The electrician assured me that when that breaker is switched to the OFF position, no damage can happen to the pump or the house if the tower is struck. Is this true?

 

[Baluncore]

The electrician assured me that when that breaker is switched to the OFF position, no damage can happen to the pump or the house if the tower is struck. Is this true?

If the foot of the tower is in contact with the Earth then it is probably sufficient to open the breaker to isolate the tower from the pump and house.
Once the new metered power is connected at the tower, the cable from the breaker to the tower should be removed. That will separate the systems and make the pump and house quite independent of the quality of the tower ground.

 

[jim hardy]

There is a breaker at the water pump that connects to the tower.

Is there a third "grounding" or "bonding" wire connecting your breaker box or pump to the tower ? Sometimes it's the metal conduit itself, sometimes it's a green or bare wire inside the conduit, sometimes it's a bare wire around which the other two are wrapped and strung overhead.

That's a path for lightning to get from the tower into your house. When they show up to finish the job you want them to remove that wire and any metal conduit going to the tower.

 

[jim hardy]

Long ago, in a thread far away...

My education on that was in 1979, at my brand new house i was using a drill outside when one of those sudden summer thunderstorms came up. I was downright smug, the house was wired with good grounds and i was only twenty feet from the ground rod at my service entrance. The drill was a metal housed Craftsman with three prong cord, one of Sears' best I thought i was really safe.

A lightning bolt hit the pole with a tremendous crash. At that instant the drill became a handful of fire and my feet too. I was paralyzed for about a quarter second, long enough to holler "Gaahhh", and when it let go i threw the drill.
Instant education - my metal drill was connected by metal wire all the way to bottom of a lightning bolt.
That lightning bolt elevated the pole, the Earth at bottom of pole, the Earth at my service entrance ground rod, and my drill to heaven knows what potential. I experienced the ground voltage drop between my service entrance twenty feet away and my feet. Without that service entrance ground rod i'd have experienced the ground voltage drop all the way out to the pole, doubtless a whole lot more.

Grounds along the way will help.
But don't leave the receptacle grounds in your house connected by a metal conductor all the way to that tall tower.
Make lightning come through the Earth to get in and it'll probably go someplace else instead.

 

[OCR]

...holler "Gaahhh"...

My holler "Gaahhh" is more akin to a screech, as such... AAAaaahhh !

I embarrassed myself in front of my wife with that noise when, by accident, I came in contact with her electric garden fence...
Well, actually... I embarrassed myself in front of myself, too. .. ...lol

 

[OCR]

... sometimes it's a bare wire around which the other two are wrapped and strung overhead.

Yeah, I think we always called that... Triplex . ?

 

[jim hardy]

Yeah, I think we always called that... Triplex . ?

The circuit breaker will disconnect the two power(Hot) conductors
but will not disconnect a Neutral or a Bonding conductor .

That's why (s?)he needs to verify they're gone.

Of course Janelle has an 80 foot metal tower not a wood power pole.
but principle is the same...

Lightning at top of pole has an all metal path into your house.
That bare copper wire down the pole carries a lot of it directly into earth. It goes to bottom of pole where it's wrapped into a spiral for max surface area to conduct as well as possible..
Ground rod at house service entrance helps too.
Still,
During that brief instant when it strikes the pole your household appliances are hardwired through their three wire grounded cords directly to the bottom of that lightning bolt. That's what almost got me.

@JanelleNica
That wifi tower is a lightning rod, as you suspect. Its wiring ought to be separated from your house wiring by as much physical distance as you can arrange.old jim

 

[jim hardy]

PS

that's why , when copper thief urchins chop a piece out of that unimportant looking bare wire running down your pole, you should inform the power company right away..

 

[OCR]

That wifi tower is a lightning rod, as you suspect. Its wiring ought to be separated from your house wiring by as much physical distance as you can arrange.

that's why , when copper thief urchins chop a piece out of that unimportant looking bare wire running down your pole, you should inform the power company right away..

 

[jim hardy]

Thanks, @OCR and @davenavenn and @dlgoff ...

old jim

 

[dlgoff]

Here's an article that may be of interest from http://lightning.org/

It's Electrical Safety Month! Let's include LIGHTNING in our electrical safety plans and discussions.

 

[OCR]

Thanks for the link, dlgoff...

And, here's another Lightning Safety Resource...

 

[jim hardy]

A picture is worth a thousand words.
OCR's link has a tab "How People are Struck by Lightning" with this dramatic picture :
(don't know why it's right shifted)

In your imagination,
Replace the tree with Janelle's tower or my power pole
and replace the fence with the ground wire going into a house.

Ground rods help divert strikes into the earth
but the kiloamps in a big lightning bolt will overwhelm them.
See also picture #3 just above, "Ground Current".

 

[dlgoff]

A picture is worth a thousand words.
...
See also picture #3 just above, "Ground Current".

Pictures indeed.
Step Potential when ungrounded and when grounded.

 

[jim hardy]

Step Potential when ungrounded and when grounded.

I still think that's why tropical wading birds sleep standing on one foot.

 

[Tom.G]

I still think that's why tropical wading birds sleep standing on one foot.

OFF TOPIC: (mostly)

http://www.sciencemag.org/news/2017/05/how-flamingos-sleep-while-standing-one-leg
How flamingos sleep while standing on one leg

By Ryan CrossMay. 23, 2017 , 7:15 PM

After a long day at the zoo, sore feet and stiff legs might make you wonder how flamingos get any shuteye while precariously standing atop a single stiltlike leg. To figure out how they do it, scientists placed juvenile flamingos atop a force platform, essentially a hypersensitive bathroom scale, and studied how the birds’ tiny muscular movements allowed them to maintain balance over their bodies’ subtle sways. While standing and grooming, the sway was large, but it decreased sevenfold while the birds slept on one leg. It appeared that the birds simultaneously exerted less muscle force and held a steadier position while asleep, the researchers report today in Biology Letters. Next, the team used two fresh flamingo cadavers to find an anatomical explanation. Although birds have the same bones in their legs as humans, their thighs are oriented horizontally, so it looks like they are permanently holding the yoga chair pose. The scientists stably propped up the dead birds on one leg by placing the foot under the body’s center. This effectively locks the leg joints in place, preventing the knee from flexing while allowing the joint to remain fully extended. Bony articulations in the joints may explain the passive locking mechanism. And although the scientists are careful to note that this study didn’t directly measure muscle activity, it’s the first evidence to suggest that flamingos, and perhaps other birds, sleep on one leg because it simply takes less energy.

 

[jim hardy]

OFF TOPIC: (mostly)

not at all ! THANKS !

That's the 'how' of it .http://www.smithsonianmag.com/smith...ian-why-do-flamingos-stand-one-leg-180956323/

Hallager says it may all be overthinking—or, that at the very least, scientists have a lot more studies to go before they can say the issue is settled.

“There’s really no good explanation,” she says. “We think that simply it’s more comfortable,” says Hallager.