Ground Rod in Water

[John Szegda]

Hello

I need to drive a ground rod for My new Hydraulic Tower Foundation. My concern is the ground two feet bellow the concrete block is saturated soil. As water is a good conductor of electricity, would this create any equipment problems.

John

[Rob Beckers]

I'm not following John...
If you're lucky enough to have wet soil 2' deep it will just make that ground rod more effective. What 'equipment' are you expecting to fail?

-RoB-

[John Szegda]

Hi Rob,

I have two fish ponds close to the tower foundation. My concern was that the fish would fry and the equipment such as pumps, filters would be damaged. But, it is good news that water would benefit the ground rod.

John

[Steven Fahey]

If it's a lightning strike scenario, then the tower is being hit whether the ground rod is there or not. If or when the tower is struck by lightning, there can be secondary effects on the fish pond whether you have a ground rod or not. Grounding the tower with a rod and proper conductors reduces damage to the tower, the turbine, and lessens the chances that electrical devices downstream are damaged, too. But unfortunately, the lightning strike occurs and is concentrated at the tower's location because the tower is there. Maybe there are ways to protect the fish ponds from the ground currents (but I wouldn't know).

[Ben Colla]

Hello

I need to drive a ground rod for My new Hydraulic Tower Foundation.

John

*Disclaimer* I aint an electrician.

Are you sure? If your hydraulic tower is what I think it is (ie, from www.f-n.cn) sitting on about 7meters of concrete, it's going to have a damn good ufer ground anyway. I'd be surprised if a single extra grounding rod would make a significant difference with regards to a lightning strike, with this particular tower.

Read Robs write up here (http://www.solacity.com/Lightning.htm)

[edit] I bolded something for extra emphasis.

[Rob Beckers]

Regarding Ufer grounds: They only work if you cast the concrete directly into the hole, without formwork (or removed the form after, and backfilled). The concrete needs lots of direct soil contact, so its salts can leach out and mix with the soil, increasing conductivity. With that in place, an Ufer ground works very well!

-RoB-

[Rob Beckers]

The trick to protecting the fish pond and equipment (if needed) is to try and keep it all at the same potential in case of a direct strike. This can be done by running a ground line around the fish pond, and pounding ground rods in every so often (see my article). That will still set up large ground currents in case of a strike, but should minimized the potential difference. For the equipment the question then becomes the potential difference between the pond area and the wiring, so some type of surge arrestor to tie it all together would be needed as well (To keep it cheap a Delta arrestor could be used).

-RoB-

[John Szegda]

Hi Rob,
Very good article on grounding. After reading your article and review of the ground rod layout, I was wondering if a sacrificial cathodic protection system would work better by the use of zinc anodes instead of ground rods.

John

[Ralph Day]

That idea might require some deeper research. If you've ever removed a sacrificial anode from a water heater you've seen what happens to them in practice. Would the ability to ground significant amounts of current be affected by the corrosion? And then there's the fact that they're sacrificial...they disappear eventually.

Ralph

[Rob Beckers]

Hi Rob,
Very good article on grounding. After reading your article and review of the ground rod layout, I was wondering if a sacrificial cathodic protection system would work better by the use of zinc anodes instead of ground rods.

John

No sure what you're trying to gain: Regular ground rods will work fine, and last a very long time (without cathodic protection).

-RoB-

[John Szegda]

You are correct Rob. This is getting to be an expensive project. I started with 8 gold fish that had grew to large for their tank. I decided to build a small pond. Some people in town had the same growth problem and asked if I could take them or they would have to destroy the fish. Well five years later I have over 240 fish. After My neighbors chickens were hit by lightning, I felt some responsibility to protect the fish. I will place the ground rods around the perimeter of the pond and tie them to the turbine tower.

John

[Rob Beckers]

John, without a shred of proof I would guess that your fish will actually be fine without doing anything extra. Unlike the chicken they are surrounded by a medium that conducts fairly well, so a nearby lightning strike should keep the potential (Voltage) of the water in the pond at about the same value everywhere. The pump and other electrical stuff will not be so lucky though, since their wiring will be at a very different potential than their casings.

In any event, what you're looking for is described as "perimeter ground" in the lightning article (http://www.solacity.com/Grounding.htm).

-RoB-

[Russ Bailey]

If Rob is wrong you can invite your friends to a 'fish fry'!:toung:

[Dave Turpin]

As a sailor, I can tell you that lightning rarely, if ever, strikes water. Water cannot develop a charge to attract it. And I have been in some pretty rough storms. Lightning will go cloud-cloud or cloud-ground or cloud-golf club or cloud-wind turbine. The fishies should be fine. The chickens, cows, alpacas and moose are on their own.