Wire Rope for ground wire

[Bigbear]

I know you should use copper wire to hook up to ground rod.  I have many feet of wire to run to the ground rods and wondered if heavy wire rope (cable) would work, say 1/2" thick.  Other than rust, would it work.  Seems like if the lightning hits the metal tower, or solar panel rack, also metal, it could just as easy follow aircraft cable to the ground rod.  Any advise would be appreciated.  BEAR

[nanotech]

Since I have no idea about your location or setup, I'm just asking....

Why not sink another ground rod at the tower?

Relieves the worry of whether the wire would work, has Fozzy tripped over the wire and disconnected it, has the neighbor kid run over it with the lawn mower, etc, etc.

[terry5732]

You will never ground lightning through a wire. Get over this notion. Try learning how to avoid lightning strikes. Grounding is for tripping circuit breakers in a compromised insulation situation.

[Bigbear]

OK, how do you avoid lightning strikes?, I must be missing something here.  I will have a ground rod at the AirX wind generator tower, the solar panel rack, the battery/inverter building, the house AC panel, and probably one at the propane gas line, and one at my shallow well.  I was wanting to tie all of these together and form one universal ground.  I just wondered if the 1/2" aircraft (steel) cable would work to tie all of the ground rods together as opposed to solid copper wire.  We live 1/2 mile back in the woods, no kids to trip over the cable, and even then it will be pretty close to the house, so no one, other than me should trip over it.  I would also like to bury it at least a couple inches underground to avoid this.  Thanks, BEAR

[TomW]

Terry;

Gee, I have to disagree here. Grounding gives an initial path to ground. Not gonna argue it but sometimes I wonder about the advice you dispense. Clearly better for it to be able to find a direct path to ground than through your wiring, etc. Dissipators work too but not always.  You are comparing apples to oranges here I think talking about tripping breakers in a compromised insulation situation as you put it. We are talking about keeping strikes out of the wiring. Even simple things like sharp bends in cables can divert part of the force and is commonly used on RF equipment as another barrier to high voltage intrusion. Just hate for someone to take this advice and leave things ungrounded then pay for it in lost equipment

Where do you get this information? I would really like to see it because it is contrary to every procedure I have encountered grounding communication towers and other sensitive equipment. Regardless, I would not use galvanized cable for the system, either.

I am open to new information, if you have it but not interested in hearsay.

Cheers.

TomW

[terry5732]

Start with this site for basics :  http://www.codecheck.com/q_a_electric.htm

I generally dislike much of NEC but they have this pretty well right

[Norm]

  Thanks for the link to the part about lightning

rods it does make a lot of sense.

     ( :>) Norm

[Old F]

Big Bear short answer  any ground  is better than no ground at all use the steel cable if that all you got .

By putting it in the ground  to keep from tripping over it  will make it a better electrical  ground.  

Have fun play safe

Now for the rest of the story

Terry  got this from the site you listed

Quote

A...David Buxton <David.Buxton@tek.com>

Newsgroups: alt.home.repair

Subject: Re: Ground aluminum siding?

Date: 16 Apr 1997

First of all, lightning rods are not designed to attract or conduct current from lightning. They are designed to dissapate and prevent the build up of the negative static charge that is necessary to cause a lightning strike. That is why they are made with a sharp point on the end. A sharp point on the end of a conductor will force ions into an ever-decreasing amount of space until their electrical potential forces them to "escape" or "jump" into the surrounding atmosphere thereby neutralizing the difference in potential of the lightning static field to ground.. If lightning rods were intended to be conductors of lightning, they would be spherical on top to retain, and therefore attract, as much of the opposite charge (negative), to lightning static field charge (positive). After all, in electricity, as in other things, opposites attract. The spherical top retaining a charge can be observed at work in a Van DeGraff (sp?) generator.

Also, if a lightning rod were meant to safely conduct the thousands and thousands of amps of a lightning strike, it would be a few feet in

diameter with a cable the diameter of a tree trunk running to a ground rod as big as the lightning rod. Anything else would melt under the demands of such a large current surge before the full charge was transmitted to the ground. All this, however, has little to do with the subject at hand. What course lightning (millions of volts) takes and what course standard household current (240/120VAC - nominal) takes, are two different things.

Lightning can jump several miles through air with no other apparent conductor, household voltage can do 1/2" tops. If lightning can go through

even 1000 feet of air, why can't it go through a few layers of 3/4" plywood and 1/2" sheetrock and, conversly, through you, like a microwave

through a cheap burrito in a convienence store? Therefore, attracting lightning is a worse idea than repelling it. Hence, lightning rods.

Now the only thing the above did not take in to account is skin affect.

Lighting can and has done some really strange things.

 Poor or no ground is one reason for a strike and on the other hand why people have survived being hit.

The rest is spot on and to think it was Ben Franklin who first work it out

So a direct strike can be the result of poor or no grounding.

And  we ground to prevent  a strike not survive one.

A lot of lighting damage is do to induced voltage from a close by strike.

   And a good ground system is all ways a good idea for a number of reasons .  

Terry in the rush to be help full you  just got a little a head of your self. And left a few things out.

No big thing.  We have all done it one time or another.  

Old F

[SmoggyTurnip]

This lightning rod IS designed to carry the current of a lightning strike:

The CN tower gets struck by lightning about 75 times a year and it is designed to conduct it to ground.

Sure the conductor has to carry VERY high currents but only for

milliseconds.  

If lightning rods were only designed to bleed off charges why would you have to use such large conductors for them are they "bleeding off" 40 amps.

I'm with Tom on this one.

.

[Old F]

Big bear  

I for got to add seeing that you are using more than one ground rod and are tying them together .

The steel cable will work and should be help full in handeling  lighting strikes.

And you  only need to put the cable  down an inch or two just enough  to keep from tripping or mowing over it.

Terry see what I mean about getting a head of one self   LOL

Old F

[Old F]

 OOps

And  we ground to prevent  a strike not survive one.

I ment to say we ground to prevent a strike and surive one.

Old F

[TomW]

The conductor size to ground may not have a big impact.

Once current starts to flow in extreme amounts the air will ionize and then the air itself becomes a better conductor and the process is self sustaining.

Regardless, I ground anything outside that has connections to the electrical system on the farm. I also put sharp bends in any incoming cables. When [not if] lightning hits here I want it to have an easy path to ground that does not include my stuff.

Another point is that the top wire on power feed lines is tied to ground and I doubt it is for disipation and I have seen strikes hit those wires hundreds of times. They seem to be tied to earth ground at each pole, also.

Cheers.

TomW

Simple and seems to work.

Cheers.

TomW

[finnsawyer]

Note that each pole has its own ground.  That's why I think he would be better off not connecting all the grounds together.  Do a separate ground.  Why would you want to give the lightning an easy path to do mischief at the propane tank.  You want it to dissipate in the earth not be channeled to everything that's vulnerable.

[wooferhound]

I used to change the lightbulbs on TV Transmission towers. These towers were from 300 to 1100 feet tall. The really big ones had 18 Guy Wires supporting the tower. These towers were ultragrounded. The tower structure itself had 3 Large ground wires comming off the Base to 3 seporate ground rods. There were also 3 ground rods at each point that the guy wires attached to the Earth, with wires comming up to All of the Guys comming down from the tower. the tower that was 1100 feet tal had a total of 21 ground rods connected to the system.

Here is a picture I took from the top of the big tower.

[terry5732]

The top wire is the high voltage line here ~6KV

Below this are 220V, neutral (ground), and another 220V

[terry5732]

As a kid I had a stainless steel wire strung between two trees about 50 feet up for an antenna. It was connected to a shortwave radio which was grounded. I got lots of static during thunderstorms and there lightning strikes nearby commonly. This was set up for many years. When the radio was disconnected (and ground too) the next passing storm made the wire into little blackened fragments all over the neighborhood. And both trees were damaged heavily from lightning in subsequent years. After the wire was gone. Apparently you can save trees with a thin wire.

[oztules]

Woofer,

Now thats a high tower. You are far fitter than me to climb that.

Now I know where you got the facial experession in your avitar...practicing for the fall:)

...........oztules

[Bigbear]

Wow, thanks for the speedy replys.  While I was cutting the 5" vent hole through the roof for the Bosch water heater, a serious thought came to mind.  My metal B vent goes through the steel roofing, which is connected to the water heater and in turn with the LP gas supply.  I wonder if the gas line ground rod should be left out of the loop.  Sooooo many questions, so little time, move in date is this Wed.  Thanks for all your help guys.  BEAR

[DanG]

My opinion only - if you decide to assemble RE components then your obligation to

protect people comes first, then property, then your RE components. You can't tell who will be sheltering from a storm in your place, or if you'll be there awake when a lightning strike occurs, etc.. Even if its a constant drain of effort and money, or a delay in installation and operation, safety is number one priority.

A better to alternative to steel is aluminum cable. I'm sorry if you don't have it on hand at the moment but cost wise it is cheaper than copper...

My opinion is never ground with steel cable - its resistance, especially in fine strand form, is very very high compared to copper and even more so after its huge surface area gets attacked by rust as most conduction through a wire occurs near the surface. Lightning induced voltages try to seek the quickest path to ground, likely to be your copper wiring even with air gaps and several layers of insulation when the initial surge is pushing against a high resistance braided steel circuit path.

Loosely woven multi-strand aluminum is used in commercial lightning rod systems to provide the shortest possible path from tops of structures to its own earth ground. If you decide to use aluminum for grounding then I'd use aluminum for the drop cables also. Your AC and control wiring hopefully will thrive in the ground 'shadow' of the tower & guy anchor grounds with their huge shortcut to ground - but the AC section needs its own ground alongside the cable bundles wiring path so when lightning jumps into it there will be an easy path for it to jump back out and dissipate into earth ground before it gets near the rest of the system.

~

[sahlein]

Woof,

How long did it take to climb that monster??

Sahlein

[wooferhound]

It would take 1½ hours to climb and replace the Lightbulbs

and then 30 minutes to climb back down and check the bulbs