Stainless steel cable for ground "Rod"??

[Bob F]

I acquired a length of 3/8" stranded stainless steel cable (from sailboat rigging) at a metal recycler. I am planning to use this as my ground "rod" for my house electrical system. Is there any reason this would not be a good choice for my grounding system if I run it down 15 feet, well into the water table, which is 7-10 feet down.

I will do this by using PVC pipe and water pressure to tunnel into the ground, inserting the cable, then pulling the PVC out.

Should I leave my current galvanized rod connected also if I do this?

[Paul Franklin]

Conductivity:

Copper at room temperature (300K) is 5.8e7 [1/Ohm/m].

304 SST at room temperature (300K) is 9.8e5 [1/Ohm/m].

So copper is quite a better conductor. Is it enough to matter? Probably not under benign conditions where only stray leakage currents flow into the ground system.

If there's a lightning strike or a hard fault from power line to ground...that's a different story. IIWM, I'd want the best low resistance ground.

Not to mention that code in many areas requires you either prove the ground resistance is low enought using special equipment, or use a system of two copper ground rods with specified length, spacing and diameter.

Again, IIWM, I'd go with the code approved solution. It's a safety issue, and a poor ground can prevent surge suppressors and electrical noise filtering circuits from working properly.

HTH,

Paul F.

[Jim Elbrecht]

Man, I consider myself a cheap and innovative SOB---- but even I would spend the $12 on a proper copper ground rod when the results of cheaping out might cause death or loss of my house.

Jim

[RBM]

Considering it is not an Nec approved method, I'd say, go for it, but leave the approved grounding method intact. Kinda like an enima on a dead person, can't hurt

>

[Bob F]

I've never seem a real copper ground rod. Even the copper colored ones I've seen are merely copper plated steel, and the more common ones are galvanized steel. Certainly, none of the "big-box" rods are copper.

One of my considerations is to get the rod down into the ground water, and the commercial 8 foot rods don't do that well. The stainless seemed like something that would do that, and would last a long time, but I guess I do need to re-think this on the conductivity basis.

I understand 3/4" galvanized pipe is code approved for ground rods, so maybe I should get a couple 20 foot lengths of that.

[Stormin Mormon]

Is an enima something that leaves me wondering?

[gfretwell]

You can get 10' rods and even segmented rods that screw together. 40 foot rods are not all that uncommon in Florida in some special circumstances like radio towers and toll booths. They join four 10' sections. You need a drive cap to save the threads for the next rod.

[John Grabowski]

*It may work fine as a grounding electrode, but I prefer to stay with approved methods. In your case I would be concerned about your connection to the electrical panel or meter. Usually those terminations are only approved for copper and aluminum conductors.

After you make your tunnel for the stainless cable to be inserted, what will cause the tunnel to compress around the cable to make good contact with the earth?

[Ashton Crusher]

There will be a considerable difference in surface area between what you get with a 1" or so diameter ground rod and the 3/8" cable. Part of the benefit of the rod would be, I would think, that his has substantial surface area.

[salty]

The stainless won't last long in that application. Stainless requires oxygen to maintain it's corrosion resistance. Crevice corrosion will set in pretty quickly in the application you describe.

[Tony]

If for some reason you want to add the stainless cable, yes leave the current galvanized rod connected. If you are worried your current ground rod is not sufficient, you may want to update it to latest code. I *think* that is 2 10' rods 6' apart. If it's new construction the ground starts out with all the rebar in the footer. It has to be electrically connected and inspected before the footer is poured. Part of the rebar, or maybe copper wire from the rebar in the footer is then attached as your ground without the 10' stakes. (I think that is right?) I just installed 2 10' ground rods I think 6' apart so I can have a service going directly to the garage. I'm not sure about all of that, I was relying on my brother, an electrician, to do the work and I was the helper. Well not exactly. He let me hammer in the 2 10' ground rods. (was ready to rent a big hammer drill if needed but it wasn't needed).

To avoid 2 bills which the power co. charges commercial rates for the

2nd one, I'm having a "current transformer" installed out on the pole with the transformer. From the pole there will be a service going to the house, and a second one going to the garage. The "current transformer" monitors both services and powers a meter out on the pole so I only get one bill. And they won't have to get out of the truck to read the meter since it will be a newer infra-red optical output that is read from a hand held unit pointed out of the truck window.