Any thoughts on electrically ground a tall stove-pipe (and support pole)?

[kebwi]

Re: Any thoughts on electrically ground a tall stove-pipe (and support pole)?

Do you actually get lightning strikes in Seattle ?

I must be like 1:10,0000,000

Maybe what you need is a tinfoil hat for when you are cooking.

Thunder is infrequent enough that people really sit up and notice it. In all honesty, this thing will never be hit by lightening, what with the nearby tall trees and the rarity of lightening...but of course I have to take it seriously.

[Neil2]

Re: Any thoughts on electrically ground a tall stove-pipe (and support pole)?

Do you actually get lightning strikes in Seattle ?

I must be like 1:10,0000,000

Maybe what you need is a tinfoil hat for when you are cooking.

[Gulf]

Re: Any thoughts on electrically ground a tall stove-pipe (and support pole)?

"FYI, ebay -- which is sometimes a good place to get stuff -- has pretty bad deals on grounding rods."

It's not as much the grounding the rod that costs so much, It is that 1" X 1" X 8 foot box that drives the price up .

All residential grounding wire that I am familiar with is bare. I don't remember what size is code down here but, I think it is 4 ought. An electrical supply would be able to answer that question and should be able to sell it to you by the exact the exact footage that you need.

[kebwi]

Re: Any thoughts on electrically ground a tall stove-pipe (and support pole)?

FYI, ebay -- which is sometimes a good place to get stuff -- has pretty bad deals on grounding rods. You can get a 5/8" (that's the thicker kind, compared to 3/8" the other popular diameter), 8' long (compared to 4' which is common on ebay) copper-plated steel grounding rod and Home Depot or Lowes for around $11. ebay, for 3/8" x 4' is around $10-$15. Crummy by comparison.

Any idea what gauge copper wire I should use to connect the base of the pole to the rod buried in the ground? The distance will only be a couple of feet. I might also run a similar wire across the support arm from the stove-pipe to the support pole on the off chance that the support arm is not of sufficient manliness to properly channel a lightening strike, so that would be about four feet in length.

Does copper wire like this need to be coated or is bare wire, exposed to the world, fine?

Cheers!

[kebwi]

Re: Any thoughts on electrically ground a tall stove-pipe (and support pole)?

One last suggestion. If depth is a problem, why not use the same idea of the coil. But, with a liile bit of a twist. Make a larger coil, but bury it shallower. I don't really think that it has to be deep. It just has to have enough surface area sufficently underground to complete the ground. Since you are not having to follow a code that I remember you mentioning, why not bury the ground rod on it's side?

I'm planning on angling or otherwise putting the rod on its side somewhat, as required by the hole I dig. I think the reason rods are intended to go deep is because the top of the soil (one or two feet) dries out and doesn't conduct as well.

But yeah, putting it on its side with the same overall rod-to-ground contact has occurred to me.

Cheers!

[Gulf]

Re: Any thoughts on electrically ground a tall stove-pipe (and support pole)?

One last suggestion. If depth is a problem, why not use the same idea of the coil. But, with a liile bit of a twist. Make a larger coil, but bury it shallower. I don't really think that it has to be deep. It just has to have enough surface area sufficently underground to complete the ground. Since you are not having to follow a code that I remember you mentioning, why not bury the ground rod on it's side?

[kebwi]

Re: Any thoughts on electrically ground a tall stove-pipe (and support pole)?

Yep, it would seem to be a natural fit to exploit the post hole as a start for the rod. Unfortunately, my post hole will be almost perfectly insulated. It isn't actually a hole so much as the gap between a brick retaining wall (obviously pretty nonconductive) and the back of the oven stand (concrete blocks) and the concrete slab on which the entire oven sits extends within an inch or two of the retaining wall so the hole will have a concrete floor under it. I'll put some gravel at the bottom before I pour the concrete so it will drain any rain water into the crevice between the concrete slab and the retaining wall, but there's no way to dig down there, so the rod can't go there.

Nope, the hole for the copper rod starts at ground level (up on top of the retaining wall I expect).

Oh well. :-)

Cheers!

[Gulf]

Re: Any thoughts on electrically ground a tall stove-pipe (and support pole)?

Sorry Kebwi,
No experience with rocky soil and 8' is all I have ever delt with. They probably use a rotary hammer in that kind of terrain. If you haven't poured the base for your pole yet, you could coil a good bit of bare copper wire at the bottom of it and run it up the side of the pour. I would cover it a little to keep most of it seperated from the concrete.

I'm not even sure that I would go to the trouble, just throwing out ideas.

[kebwi]

Re: Any thoughts on electrically ground a tall stove-pipe (and support pole)?

".......Sounds expensive. I actually suspect the 4" to 3-1/2" aluminum support pole doesn't provide more metal for electricity to flow through than the 7" double-walled steel pipe"

About 30 bucks for an 8' grounding rod. $2.50-3.00 for the clamp and about $1.25 per foot of bare copper wire. I do agree that the steel in your chimney would probably be a better conductor than the aluminum pole. That is why I would ground them together at the top and only ground the aluminum pole to earth. Hopefully, a charge would follow the better grounded aluminum and away from the oven.

I was perusing ebay and hadn't found 8' rods yet. Found lots of 4' and a few 6'. If I used the 4' I would probably buy two or three (not sure if the proper wiring is serial or parallel w.r.t. the base of the pole.). My yard is riddled with rocks the size of a cantelope, I can't even drive 12" tent stakes without stopping to dig out the hole as I go. Going down 4' for the shorter rods is going to be almost impossible; it's going to take me a full day to dig that far down (times 2 or 3 for multiple rods). Going down 8' will definitely be COMPLETELY impossible in my yard (without renting a backhoe and destroying the yard in the process).

[Gulf]

Re: Any thoughts on electrically ground a tall stove-pipe (and support pole)?

".......Sounds expensive. I actually suspect the 4" to 3-1/2" aluminum support pole doesn't provide more metal for electricity to flow through than the 7" double-walled steel pipe"

About 30 bucks for an 8' grounding rod. $2.50-3.00 for the clamp and about $1.25 per foot of bare copper wire. I do agree that the steel in your chimney would probably be a better conductor than the aluminum pole. That is why I would ground them together at the top and only ground the aluminum pole to earth. Hopefully, a charge would follow the better grounded aluminum and away from the oven.

[kebwi]

Re: Any thoughts on electrically ground a tall stove-pipe (and support pole)?

Yeah, see, by that analysis alone, I barely need any grounding. I'll ground it for sure, I'm just not sure I'll obsess over it or spend $150-$200 on gobs of copper.

I'll look into it carefully as I proceed.

[Laku]

Re: Any thoughts on electrically ground a tall stove-pipe (and support pole)?

There's a formula of a sort to that kind of protection



How trees (and tall buildings/structures if conductive enough) affect protection angle

Trees all around the building alpha= 60?
Trees on two opposite sides of the house alpha = 50?
Trees on one side of the house alpha = 30?
Solitary tree alpha = 25?

Everything that is inside of that is almost perfectly protected.

[kebwi]

Re: Any thoughts on electrically ground a tall stove-pipe (and support pole)?

I seriously doubt that this thing will ever take a strike. There are several 80-footish trees in the immediate viscinity (within thirty-forty feet of the oven) and a church steeple just two lots away (to say nothing of my own house's roof, which will be of comparable height and only thirty-forty feet away).

Part of the reason for this super long stove pipe is that the oven is on really low ground. In the end, after I build this thing, the top of the stove-pipe will still be lower than that of many other roof-stove-pipes in the area. The only thing that makes it look so electrical is that it will be one rather long pipe instead of a short pipe one top of a roof (and the 14' support pole next to it).

Cheers!

[kebwi]

Re: Any thoughts on electrically ground a tall stove-pipe (and support pole)?

Thanks Gulf. Sounds expensive. I actually suspect the 4" to 3-1/2" aluminum support pole doesn't provide more metal for electricity to flow through than the 7" double-walled steel pipe, despite the pole's 1/8" thickness (since the stove pipe is two concentric walls of significantly greater circumference than the pole, and I believe steel is more conductive than aluminum, so for a given thickness it generates less resistance...I think).

Of course, there's the question of whether the support arm between the two structures is solid enough to transmit lightening from one to the other such that I need only ground one of the two structures (ostensibly the pole). I have been considering using copper pipe as the support arms between the pole and the stove pipe, just for aesthetic reasons. Perhaps this is another good reason for that approach. :-)

I'll see what copper cable costs, I don't want to spend as much on a lightening system as the rest of the system put together. Good grief.

Thanks.

[Gulf]

Re: Any thoughts on electrically ground a tall stove-pipe (and support pole)?

On the electrical poles down here they have the copper attached to the full length of the pole. The wire is twisted into a coil and attached underneath the base of the pole. When the pole is set, the weight of the pole is setting on the coil of copper. I think the coil of wire must give it more area of contact with the earth. Of course they do require grounding rods at the service entrance of the home, though. The reason copper is requred for earth contact is that steel will eventually turn into a ball of rust and probably would be less of a ground at that point. I think that your aluminum pole would have enough mass to be a good conductor. I would just run a copper ground from the top of the chimney to the pole. Then I would secure another length of copper wire to the base of the aluminum pole and then to a copper ground rod.